The final structural element of the building must not only reliably protect against precipitation and retain heat, but also emphasize the architectural merits. The shape is classified by: angle of inclination (flat, pitched); the presence of vaults, domes; number of external and internal ribs; number of planes (slopes). The more complex the system, the more likely it is that a construction crew will have to be hired to complete the work. It is necessary to choose not the simplest option, but one that is interesting from a design point of view. A hip roof is the ideal solution.
Types of execution:
- Hip - consists of two triangular slopes, their apexes resting on the ends of the ridge. The other two planes are trapezoids.
- Half-hip - differs from the first version in that part of the inclined surface is occupied by the pediment. The roof has a shortened appearance along one or two planes. Experiences less wind and snow loads. Another plus is the possibility of installing full windows or balconies in the gable area in the attic.
- Tent - triangular slopes converge at one point. The use of such a solution is advisable for a house with the same dimensions of external walls.
Features of hipped roofs:
- More uniform distribution of the load on the foundation along the entire perimeter.
- Volume reduction attic space– reduction of heat consumption for heating, complexity of organizing the attic space.
- Good resistance to wind and snow loads.
- Higher structural rigidity due to an increase in the number of external ribs.
Nuances hipped roof:
- The central intermediate and diagonal rafters converge at the ends of the ridge beam. The organization of the node is quite complex.
- External rafters are attached to the corner rafters.
- It is necessary to maintain the angle of inclination of the elements to create a plane for installing the roof.
- The slope of the corner rafters is always less than that of the central and intermediate ones. This is the longest element.
- The support is the mauerlat and ridge girder.
Instructions for selecting and calculating a rafter system
The construction of a house begins with the design of the project. Independent development of a drawing is impossible without:
- studying construction technology;
- farm calculations.
Factors influencing the choice:
- slope angle;
- hip roof material;
- weight of the “roofing cake”;
- wind and snow loads;
- seismic hazard;
- overall dimensions of the house box, the presence of internal load-bearing partitions, columns;
- planning the organization of the attic space.
The slope of the slopes is determined not only for aesthetic reasons. It's important to find golden mean between a positive visual perception and maintaining the reliability and functionality of the design. The size of the angle is closely related to almost all of the above factors:
- The use of all types of roofing materials is limited to the range of this parameter.
- The smaller the angle of inclination, the less significant the impact of wind load.
- An increase to 45-60° guarantees independent precipitation. The impact of snow cover is minimized.
- By reducing the angle of inclination, we reduce the area and weight of the entire system. The consumption of thermal energy to warm up the attic space decreases.
- The organization of the attic floor is unlikely if the slope is small.
Types of roof trusses
1. Layered design hip roof performed based on:
- external walls (mauerlat);
- run (ridge);
- on internal load-bearing partitions, columns inside the house through the floor.
The load is distributed by installing additional racks under the ridge beam. The bed distributes pressure over the entire surface internal partition(columns).
2. Hanging – used for buildings with a maximum foundation size of up to 6 ~ 7 meters. The rafters rest on the walls. Load distribution using racks, tightening, crossbars, struts. This type is rarely used for hip roofs.
Instructions for calculating the rafter system
Carrying out a drawing of a hipped roof is impossible without performing mathematical calculations.
1. The size of the run is determined based on the dimensions of the house. Standard solution: length minus width. The middle of the ridge beam is located clearly above the intersection of the diagonals of the base. The purlin line is parallel to the front walls.
2. Ridge height: H = b x tgα. b – half length end walls houses, α is the slope of the slopes. The numerical value of the tangent is determined using the Bradis table.
3. Size of the central and intermediate rafters of the slope: Lcentral line of the slope = √(H² + b²).
4. Length of the central rafter leg of the hip: Ltr.str.hip = √(H² + b²). At non-standard choice the size of the ridge, the value b is determined as half the difference in the lengths of the house and the run.
5. Size of diagonal elements: Ldn.str. = √ (Lcentral hip² + b²).
6. Calculation of the lengths of sprigs - the property of similar triangles is used. If the angles are equal, on one of the sides the proportion of lengths is satisfied, then the ratio of the remaining components of the figure will be observed: D = 3/4 C, which means: Lout = Lcentral hip x 3/4.
7. The distance between the rafters depends on the choice:
- Section dimensions, wood quality. The weaker the material, the smaller the step should be.
- The presence and type of thermal insulation layer is determined by the ease of installation of insulation (60-120 cm).
- Roofing material, its weight and geometry. The greater the total mass, the smaller the step. As with thermal insulation, the dimensions of the sheet are taken into account.
The minimum step between trusses is 60 cm, the maximum is 2 meters.
8. The formation and calculation of overhangs depend on the preferences of the residents and the height of the house. Minimum size for a 1-story building - 500 mm. The task is to protect the walls from precipitation.
Construction of a hip rafter system
Mauerlat is a beam or upper crown, the frame of a house, to which the rafters are attached. Ensures uniform load distribution on external walls. Section: 10x10 cm ~15*15 cm. Armopoyas is a reinforced concrete structure along the upper perimeter of the walls. Its task is to strengthen the base under the Mauerlat and ensure reliable adhesion to the roof.
Mauerlat installation options:
- On reinforced concrete belt using embedded studs and anchors.
- Anchors into the body of the wall are one-story brick houses with a slight slope of the hip roof.
- To the last crown wooden log house or the top trim of a frame structure.
- Installation on studs embedded in brickwork.
- Staples driven into wooden inserts inside a brick wall and the body of the mauerlat.
- Unheated steel wire laid at the time of construction of the facade.
- On studs fixed in the wall with a chemical anchor - a two-component composition. The glue is injected into the drilled holes in the masonry of the house, dries, and securely holds the element.
Peculiarities:
- The number of studs, brackets, anchors should be greater or equal to the number rafter legs.
- Roofing material is laid under the timber or bitumen mastic is applied to the base.
Installation Guide:
- The marking of holes for studs and anchors is carried out by laying slats on the fasteners and then hitting the surface of the wood. Drilling is carried out along the notches. The timber is placed on studs and secured with a washer and nut.
- Wire connection - the ends are passed over the planks and twisted.
- Extension schemes for long sections:
- The floor beams are laid either at the same level with the Mauerlat, or on a block fixed to the wall. Step – 0.6-1 meter.
- Screed the Mauerlat with slats, to which the racks for the purlin will later be fixed.
- After completion, markings of rafter placement are made on the surface of the Mauerlat.
Installation of purlins
The ridge beam experiences significant loads and is installed on racks. The correctness of the work depends on:
- Symmetry of design, uniform weight distribution.
- Reliability of a hipped roof under maximum wind and snow loads.
Brief installation instructions:
- The design (hanging, hanging) depends on the presence of internal load-bearing partitions. The racks can be attached to screeds or floors.
- In houses with large sizes the structure must be strengthened with struts to ensure resistance to loads.
- The material for the ridge and supports is chosen to be the same cross-section, at least 100x100 mm.
- Before work, carefully measure and determine the central and extreme points of fixation of the racks. Their number is affected by the length of the run. Step – no more than 1 meter.
DIY rafter installation
There are two orders of work:
- First the central rafters, then the diagonal ones. The spigots are installed last.
- Installation of diagonal elements, then central ones.
The first method is considered simpler. The second allows you to check symmetry at the initial stage of work.
Options for attaching to the Mauerlat:
- Hard - a cut is made in the rafters, the depth of which is no more than 1/3 of the width of the beam. The recesses (saddle) can be cut according to the template.
- Sliding - used for structures that shrink. For fixation to the Mauerlat use special fasteners, floating supports for rafters. With this method, the connection of the legs above the skate is done in a hinged manner.
- Layered - the end of the rafter rests on the mauerlat. The overhangs of a hip roof are formed by extending the legs with additional slats (fillies) of a smaller cross-section. This method allows you to save on material.
Design of the ridge unit of the central, intermediate opposite rafters:
- Butt joint - a connection with cutting the ends of the legs at an angle. Conjugation of sections is carried out. The assembly is fastened with nails. Additional fixation will be provided by a metal plate or wooden plate.
- Overlapping - rafters overlap each other with their side surfaces. Fastening – hinged (bolt), nails.
- To the ridge beam - the connection of the rafter section with the side surface of the purlin.
Features of installing diagonal legs:
- Placement of the upper unit with the cut-off stop of the sloped rafters in lateral surface central elements of the system.
- To strengthen the diagonal legs, which experience the greatest load, the installation of truss trusses and racks is required.
Installation of the splices to the diagonal rafter is carried out by sawing and joining with its side surface, fixing with nails.
Upon completion of the work, it is necessary to check the equality of the angles of inclination and lengths of opposite rafters, compliance with the plane of the slopes and hips.
Nuances and possible errors
1. When purchasing lumber, you need to make sure that:
- Wood moisture content does not exceed 20%. When drying, the board changes geometry, which will lead to a change in lengths and straightness. Violation of proportions entails leakage and reduced resistance to wind and snow loads. The most best quality from wood harvested in winter period in regions with cold climates. Before making a purchase, contact the seller with a request to measure the humidity.
- There are no cracks, ingrown knots, or traces of insect activity in the body.
- When purchasing laminated veneer lumber, make sure that the seller and manufacturer are honest. The use of low-quality products will lead to a breakdown in strength.
2. Elements of the rafter system can be ordered from enterprises specializing in the construction and manufacture of turnkey houses.
3. Before installation work begins, wood is treated with antiseptics and fire retardants.
4. The length of the purchased slats sometimes does not correspond to the calculated size. Extension technology:
- Oblique cut with maximum adjustment of mating planes. IN through hole the bolt or stud is inserted with tension, without play; tighten the nut.
- Overlapping more than 100 cm. Carry out using nails, bolts, studs in a checkerboard pattern.
- Butt cross-section - sawed off at 90°. The docking point with opposite sides covered with overlays. Fastening - as in the previous method.
5. The nodes are additionally fixed with metal fasteners: corners, plates and others. Each of these elements has holes for hardware. It is advisable to use products with oval slots that allow minor displacements of the mating surfaces. During shrinkage and exposure to loads, the rigid connection may break.
- Lack of load and weight calculations. Exceeding the permissible values leads to the destruction of the foundation and roof frame. You can perform the necessary calculations yourself or use online calculators. Involving specialists is the best solution.
- The step exceeds the calculated value. By saving on materials, the master will acquire many problems.
- The plane of the slopes and hips is not controlled using a cord. Deviations will cause the roof to sag, disrupt the tightness and reliability of the roof, even to the point of deformation.
The hipped (hip) roof is considered one of the most complex structures. Like any other, it has its advantages and disadvantages. To make an informed decision, you need to familiarize yourself with the real performance characteristics hipped roof.
Flaws
As you can see, the advantages of a hipped roof are questionable, but the disadvantages are significant.
Practical advice. Professional builders recommend choosing hip roofs only in exceptional cases when other options are unacceptable for various reasons.
Types of hipped roofs
Every country has its own building traditions and style preferences. What types of hip roofs are used by architects?
Table. Types of hipped roofs.
| Hip roof view | Brief description |
|---|---|
| The most simple roof, has two hip slopes of a regular triangular shape and two inclined ones in the shape of a trapezoid. The lower the angle of inclination of the slopes, the greater the overhang can be made to protect the facade and the surrounding area. |
| All slopes converge at one point, the roof ridge is missing. It is used as a covering for buildings of regular square shape. |
| A successful attempt to improve the classic hip roofs. The hip slopes are slightly lowered, which allows installation small windows. It has a significant drawback - due to the installation of windows, the already difficult installation of the rafter system becomes even more complicated. There are more complex options such a roof - another small hip slope is made above the window. |
| It has low pediments and small hips above them. The peculiarity of this design is that all rafter legs rest on parallel load-bearing walls. Due to this, the design is slightly simplified and the attic space is increased. |
There are no universal recommendations for choosing the type of hipped roof; each developer must make a decision independently or after consultation with architects. But you should always remember that there are other, cheaper and more successful options for rafter systems.
Step-by-step instructions for building a hipped roof
As an example, let’s look at the simplest of the listed types of hip roofs – the classic one. But even such a simple hip roof design is much more complex than any gable roof.
Important. You can start building a hip roof only after the professionals have made all the calculations. The best option is to order a house project from the relevant organizations. This will cost much less than restoring the structure after its destruction.
In private housing construction, in addition to the common gable roofs, stronger and more rigid hipped structures are often used. They are distinguished by the absence of pediments, which replace triangular slopes that cut off the ends of the ridge ridge. This configuration makes hipped roofs very attractive and economical, even though their construction increases the length of the eaves overhangs and the number of drainpipes and gutters. Therefore, they deserve the closest attention.
Types of rafter systems for hipped roofs
The design of the rafter system depends on the shape of the hipped roof. The most common configurations today are:
- Hip structure. All four slopes occupy the area from the ridge to the eaves overhang, with two side slopes having a trapezoidal shape, and two end ones (hips) having a triangular shape. A feature of the hip rafter frame is the presence of two pairs of diagonally layered rafters, which extend from the edge of the ridge and serve as supports for the trusses and trusses.
The hip hipped design is characterized by the fact that the slopes occupy the entire roof area - from the ridge to the eaves
- Dutch half hip. A device with truncated end slopes that do not reach the cornice. As a rule, they are 2–3 times smaller than trapezoidal ones. The advantage of this structure of a hipped roof is the possibility of installing a regular window at the ends of the house, as well as the absence of a sharp protrusion typical for gable roofs, which greatly increases the wind resistance of the structure.
The Dutch half-hip roof has truncated triangular slopes and part of the pediment into which a regular vertical window can be installed
- Danish half hip. It is characterized by the presence of a pediment at the ridge in the triangular slopes, which allows for full natural lighting of the under-roof space without installing roof windows.
- Tent structure. Installed on houses with a square frame. All four slopes of the hipped roof are identical isosceles triangles connected at one point. When constructing such a roof important aspect is to maintain symmetry.
The structure of the hip truss system depends on the selected roof configuration
Features of the supporting frame of a hipped roof
Let us immediately note that the rafter system of a hipped roof will be more complex compared to traditional gable structures for two reasons.
- Due to the increase in the number of inclined planes and their joining to each other. At its core, the connection of slopes is intersection lines running at a certain angle to the horizon. The joints that form an angle protruding above the surface of the slopes are called roof ribs. From them, water flows down the slopes and accumulates in grooves (valleys) - lines of intersection with the internal corner. If all planes have the same slope, then the ribs and valleys divide the angle of the base at the junction of adjacent slopes in two and create a slope to the perimeter of the building of 45°.
Four-slope rafter systems are distinguished by the absence of full pediments, instead of which there are two triangular end slopes, as well as the presence of two lateral trapezoidal inclined planes, grooves and ribs
- Due to the fact that the runs in hipped design form a closed contour, where hip (diagonal) rafter legs are located along the lines of the ribs and valleys. They are longer than ordinary beams, which are installed longitudinally along the slopes at a distance between intersections hip rafters in the top harness. But between the lower parts of the diagonal legs, short rafters, called sprigs, are mounted. Distinctive feature The frame of a hipped roof is the presence of trusses - wooden struts under the hip rafters.
The support purlins in hipped structures have a closed contour, where diagonal rafter legs are located along the lines of the valleys and ribs
The main structural elements of the rafter system of a hipped roof are:
Thus, the number of elements of the rafter system of a hipped roof is much greater than, for example, that of a gable roof, and this, naturally, increases the cost of its construction. However, in general, as we noted above, the installation of a hipped roof will not cost much more due to the savings on laying the roofing pie, since waste insulating materials and the covering flooring when cutting into a multi-slope structure will be significantly less.
Despite the fact that the rafter system of the hipped structure is more complex and expensive, the construction of the entire roof is more profitable due to the savings on arranging the roofing pie
In addition, the hipped design:
Video: gable or hip roof - what to choose
How to calculate the rafter system of a hipped roof
The supporting structure of a hipped roof can be layered if the building has permanent internal walls, or hanging when intermediate supports are not provided in the building. With a hanging structure, the rafters rest on the walls of the house and exert a bursting force on them. To relieve the load on the walls in such cases, a tie is installed at the base of the rafter legs, connecting the rafters to each other.
The use of a layered structure makes the frame lighter and more economical due to the fact that less lumber is required for its arrangement. Because of this, the layered rafter system is used in the construction multi-pitched roofs much more often. But regardless of the type of rafters used, only the correct calculation of the supporting frame and accurate markings will increase economic effect from the construction of a hipped structure.
Marking and calculation of the supporting frame of a hipped roof
When calculating the rafter system, you must adhere to following rules.
To determine the installation location of the rafters and find their length, you will need a template.
Using a template will make it much easier to measure and calculate the rafter frame of a hipped roof
The length of the rafter leg can be determined by its position (horizontal projection). There is a special table of coefficients for this, presented below. The length of the rafter is determined by the size of its projection, multiplied by a coefficient corresponding to the slope of the slope.
Table: relationship between the length and laying of the rafters
| Roof slope | Coefficient for calculating the length of intermediate rafters | Coefficient for calculating the length of corner rafters |
| 3:12 | 1,031 | 1,016 |
| 4:12 | 1,054 | 1,027 |
| 5:12 | 1,083 | 1,043 |
| 6:12 | 1,118 | 1,061 |
| 7:12 | 1,158 | 1,082 |
| 8:12 | 1,202 | 1,106 |
| 9:12 | 1,25 | 1,131 |
| 10:12 | 1,302 | 1,161 |
| 11:12 | 1,357 | 1,192 |
| 12:12 | 1,414 | 1,225 |
| Note: when constructing a roof frame for which there is no data in the table (for non-standard slopes), the parameters should be calculated using the Pythagorean theorem or using a mathematical proportion. | ||
Let's consider an example: a private house is being built in Yekaterinburg measuring 7.5x12 m with a planned height of a hip roof made of metal tiles of 2.7 m.
- First of all, we draw a drawing or sketch of the roof.
Before calculating the rafter system, it is necessary to make a sketch of the building and apply all the initial data to it
- We find the angle of inclination of the slopes using the formula: the tangent of the angle of inclination is equal to the ratio of the height of the roof to half the length of the span, in our case - to half the end side L = 7.5 / 2 = 3.75. Thus, tan α = 2.7 / 3.75 = 0.72. Using reference tables, we determine: α = 36°, which corresponds to standards requiring a roof slope for metal tiles of at least 14°, and climatic conditions Yekaterinburg.
The tangent of the angle of inclination of the slopes is determined by the well-known formula for calculating the sides of a right triangle as the ratio of the opposite side to the adjacent one
- We determine the position and edge of the ridge ridge, for which we apply the template at an angle of 36° in the middle top harness end (place of installation of the first central intermediate rafter) to a height of 2.7 m and design the outline on the sketch.
- We retreat ½ the thickness of the ridge beam from the center (key) line and install the end of the measuring rod at this point. At the other end of the slats, we make marks for the outer and inner contours of the side wall, as well as the overhang. We turn the rail to the side and from the inner corner of the outer trim we mark the location of the intermediate rafter along the mark of the internal contour, thus determining the installation location of the second intermediate central rafter.
When arranging the rafter frame of a hipped roof, the position of the central rafter legs is initially determined using a template and a measuring rod
- We carry out similar actions at all corners, determining the edges of the ridge ridge and the location of all central rafter legs.
- After planning the intermediate rafters, we determine their length from the table. In our example, the tilt angle is 36°, its tangent is 0.72, which corresponds to a ratio of 8.64:12. There is no such value in the table, so let’s calculate the coefficient relative to the line with the parameter 8:12 - 8.64/ 8 = 1.08. This means that the required coefficient is 1.202 · 1.08 = 1.298.
- By multiplying the depth of the intermediate rafters by the calculated coefficient, we find their length. Let us take into account the laying depth of 3 m, then L str = 3 · 1.298 = 3.89 m.
The length of the row and central intermediate rafters depends on the angle of the roof and the depth of their laying
- Similarly, we determine the length of the diagonal rafters, having previously calculated the laying equal to the distance from the corner of the connection of the side and end slopes to the first intermediate central rafter. According to the initial data, the position of the corner rafters is 7.5 / 2 = 3.75 m. Then the estimated length of the corner rafters will be equal to 3.75 1.298 = 4.87 m.
Corner rafters are different from intermediate device undercuts with a double bevel in the ridge area, deeper laying and longer undercut lengths for the supporting part
- We calculate the overhang using the Pythagorean theorem according to the markings made or simply add the desired size to the length of the rafters, for example, 0.6 m plus at least 0.3 m for arranging an external drain.
To calculate the length of the overhang, you need to multiply its position by the coefficient for the intermediate or corner rafters or add the planned length of the overhang and at least 0.3 m to the estimated length of the rafters for organizing an external drainage system
- Having marked all the elements of the rafter frame, we determine the length of the ridge ridge, which is equal to the difference between the length of the side and the doubled value of the intermediate rafters: 12 – 2 3 = 6 m. It is at this distance that the ordinary rafters will be installed. If we take a step of 1 m, then we will need 5 row rafters, equal in length to the central ones. In addition, in the area where the intermediate central rafters are laid, which is 3 m long, two short rafters will be installed on one and the other side edge.
- Since the short rafters (spreaders) are attached to the diagonal ones, this means that two spandrels will also be installed on the end sides between the corner and central intermediate rafters on the left and right.
Let's summarize - for the rafter frame of a hipped roof you will need:
- two pairs of hip (corner) rafters with a length of 4.87 + 0.6 + 0.3 = 5.77 m;
- three pairs of intermediate central rafters with a length of 3.89 + 0.6 + 0.3 = 4.79 m;
- five pairs of ordinary rafters 4.79 m long.
There are only ten pairs of rafters, the total length of which will be approximately 100 linear meters. We add here 6 m for the ridge beam, as well as a ten percent margin, and we get that approximately 117 linear meters of lumber are needed to make a simple hip rafter frame with struts, spacers, crossbars, trusses and fillets. But if the design includes racks and a bench, then they will have to be calculated separately or a larger percentage of the margin should be added.
Video: hip roof rafter system, installation technology
https://youtube.com/watch?v=n_Yr2QB3diMThe measuring rod greatly facilitates the work and helps to avoid gross errors when taking measurements. It is most often made independently from plywood 50 mm wide.
A few words need to be said about short rafters. They are calculated in the same way as intermediate ones: the laying multiplied by the coefficient for intermediate rafters from the table. However, the task can be simplified and you don’t have to specifically calculate the length of the spigots, since a sufficient percentage of the margin is taken, and the trimmings of the boards will be needed for the manufacture of elements reinforcing the structure - struts, spacers, crossbars, etc.
The length of short rafters (springs) can not be calculated, since the scraps of lumber are useful for the manufacture of reinforcing structural elements
Video: rafter frame of a hip roof, marking of elements and assembly
Calculation of lumber cross-section
After marking the position of the components of the rafter frame, it is necessary to select suitable lumber, i.e., determine their permissible cross-section. For calculations you will need a zoned map of snow and wind loads and thermal resistance, as well as auxiliary tables based on regulations- SNiP II-3–79, SP 64.13330.2011, SNiP 2.01.07–85 and SP 20.13330.2011.
The installation of a hipped roof includes the determination of the required cross-section of lumber, which is carried out based on an analysis of the loads on the truss structure during operation
The load from snow cover is determined by the formula S = S g µ, where S is the desired snow load (kg/m²); S g is the standard load for the real area, indicated on the map, µ is a correction factor depending on the slope of the roof. Since our tilt angle ranges from 30 to 60°, we calculate µ using the formula 0.033 · (60 – 36) = 0.792 (see note to the table below). Then S = 168 · 0.792 = 133 kg/m² (Ekaterinburg is located in the fourth climatic region, where S g = 168 kg/m2).
Table: determination of the µ indicator depending on the roof slope
| Determining the angle of the roof | |
| Tangent value | Angle α° |
| 0,27 | 15 |
| 0,36 | 20 |
| 0,47 | 25 |
| 0,58 | 30 |
| 0,7 | 35 |
| 0,84 | 40 |
| 1 | 45 |
| 1,2 | 50 |
| 1,4 | 55 |
| 1,73 | 60 |
| 2,14 | 65 |
| Note: if the slope angle (α) ≤ 30°, then the coefficient µ is taken as 1; if angle α ≥ 60°, then µ = 0; if 30°< α < 60°, µ высчитывают по формуле µ = 0,033 · (60 - α). |
|
Table: standard snow loads by region
| Region No. | I | II | III | IV | V | VI | VII | VIII |
| S g, kg/m 2 | 56 | 84 | 126 | 168 | 224 | 280 | 336 | 393 |
We calculate the wind load using the formula W = W o k c, where W o is the standard indicator on the map, k is the tabular index, c is the aerodynamic drag coefficient, varying from -1.8 to +0.8 and depending on the slope of the slopes . If the angle of inclination is more than 30°, then according to SNiP 2.01.07–85 clause 6.6, the maximum positive value of the aerodynamic index, equal to 0.8, is taken into account.
Yekaterinburg belongs to the first zone in terms of wind load, the house is being built in one of the city districts, the height of the building including the roof is 8.7 m (zone “B” according to the table below), which means W o = 32 kg/m², k = 0 .65 and c = 0.8. Then W = 32 · 0.65 · 0.8 = 16.64 ≈ 17 kg/m². In other words, it is with this force that the wind at a height of 8.7 m presses on the roof.
Table: k index value for different types of terrain
| Building height Z, m | Coefficient k for terrain types | ||
| A | IN | WITH | |
| ≤ 5 | 0,75 | 0,5 | 0,4 |
| 10 | 1,0 | 0,65 | 0,4 |
| 20 | 1,25 | 0,85 | 0,55 |
| 40 | 1,5 | 1,1 | 0,8 |
| 60 | 1,7 | 1,3 | 1,0 |
| 80 | 1,85 | 1,45 | 1,15 |
| 100 | 2,0 | 1,6 | 1,25 |
| 150 | 2,25 | 1,9 | 1,55 |
| 200 | 2,45 | 2,1 | 1,8 |
| 250 | 2,65 | 2,3 | 2,0 |
| 300 | 2,75 | 2,5 | 2,2 |
| 350 | 2,75 | 2,75 | 2,35 |
| ≥480 | 2,75 | 2,75 | 2,75 |
| Note: “A” - open coasts of seas, lakes and reservoirs, as well as deserts, steppes, forest-steppes, tundra; “B” - urban areas, forests and other areas evenly covered with obstacles more than 10 m high; “C” - urban areas with buildings over 25 m high. |
|||
Table: standard wind load by region
| Region No. | Ia | I | II | III | IV | V | VI | VII |
| W o , kg/m 2 | 24 | 32 | 42 | 53 | 67 | 84 | 100 | 120 |
Now let's calculate the load on the supporting frame from the weight of the roof. To do this, add up the weight of all the layers of the roofing pie laid on top of the rafters. We leave the rafters open to achieve a decorative effect, which means we lay all the layers on top of the rafters. The roof load on the elements of the rafter system will be equal to the sum of the weights of the metal tiles, sheathing and counter-lattens, insulating films, insulation, additional sheathing and ventilation slats, a solid plywood base and the facing material of the under-roof room.
When determining the load on the supporting frame from the weight of the roof, the weights of all layers of the roofing cake laid on top of the rafters are summed up
The mass of each layer can be found in the manufacturer's instructions by selecting the highest density value. We calculate the thickness of the heat insulator using a thermal resistance map for a specific area. We find it using the formula T = R λ P, where:
- T is the thickness of the heat insulator;
- R is the thermal resistance standard for a specific area, according to the map included in SNiP II-3–79, in our case 5.2 m 2 °C/W;
- λ is the thermal conductivity coefficient of the insulation, which for low-rise construction taken equal to 0.04;
- P is the highest value of the density of the thermal insulation material. We will use basalt insulation"Rocklight", for which P = 40 kg/m².
So, T = 5.2 · 0.04 · 40 = 8.32 ≈ 9 kg/m². Thus, the total load of the roof will be equal to 5 (metal tiles) + 4 (solid flooring) + 23 (main, additional and counter lathing) + 0.3 2 (insulating films) + 9 (insulation) + 3 (cladding) = 44 .6 ≈ 45 kg/m².
Having received all the necessary intermediate values, we determine the total load on the supporting frame of the hipped roof: Q = 133 + 17 + 45 = 195 kg/m².
The permissible cross-section of lumber is calculated using the formulas:
- H ≥ 9.5 · L max · √, if angle α > 30°;
- H ≥ 8.6 L max √, if α< 30°.
The following notations are used here:
- H - board width (cm);
- L max - maximum working length of rafters (m). Since the layered rafter legs are connected in the ridge area, the entire length is considered working and L max = 4.79 m;
- R bend is an indicator of the bending resistance of wood (kg/cm). According to the set of rules 64.13330.2011 for wood of grade II R bend = 130 kg/cm;
- B is the thickness of the board, taken arbitrarily. Let's assume B = 5 cm;
- Q r - load per linear meter of one rafter leg (kg/m). Qr = A · Q, where A is the pitch of the rafters, which in our case is 1 m. Therefore, Q r = 195 kg/m.
Substitute the numerical values into the formula → H ≥ 9.5 · 4.79 · √ = 9.5 · 4.79 · 0.55 = 25.03 cm ≈ 250 mm.
Table: nominal sizes of softwood edged boards
| Board thickness, mm | Width (H) of boards, mm | ||||||||
| 16 | 75 | 100 | 125 | 150 | - | - | - | - | - |
| 19 | 75 | 100 | 125 | 150 | 175 | - | - | - | - |
| 22 | 75 | 100 | 125 | 150 | 175 | 200 | 225 | - | - |
| 25 | 75 | 100 | 125 | 150 | 175 | 200 | 225 | 250 | 275 |
| 32 | 75 | 100 | 125 | 150 | 175 | 200 | 225 | 250 | 275 |
| 40 | 75 | 100 | 125 | 150 | 175 | 200 | 225 | 250 | 275 |
| 44 | 75 | 100 | 125 | 150 | 175 | 200 | 225 | 250 | 275 |
| 50 | 75 | 100 | 125 | 150 | 175 | 200 | 225 | 250 | 275 |
| 60 | 75 | 100 | 125 | 150 | 175 | 200 | 225 | 250 | 275 |
| 75 | 75 | 100 | 125 | 150 | 175 | 200 | 225 | 250 | 275 |
| 100 | - | 100 | 125 | 150 | 175 | 200 | 225 | 250 | 275 |
| 125 | - | - | 125 | 150 | 175 | 200 | 225 | 250 | - |
| 150 | - | - | - | 150 | 175 | 200 | 225 | 250 | - |
| 175 | - | - | - | - | 175 | 200 | 225 | 250 | - |
| 200 | - | - | - | - | - | 200 | 225 | 250 | - |
| 250 | - | - | - | - | - | - | - | 250 | - |
From the table, the thickness of the board with a width of 250 mm can vary from 25 to 250 mm. A table of the dependence of the cross-section on the pitch and length of the rafters will help you determine more specifically. The length of the intermediate rafters is 4.79 m, pitch 1.0 m - look at the table and select the appropriate section. It is equal to 75X250 mm.
Table: cross-section of lumber depending on the length and pitch of the rafters
| Rafter spacing, cm | Rafter length, m | ||||||
| 3,0 | 3,5 | 4,0 | 4,5 | 5,0 | 5,5 | 6,0 | |
| 215 | 100Х150 | 100Х175 | 100Х200 | 100Х200 | 100Х200 | 100Х250 | - |
| 175 | 75Х150 | 75Х200 | 75Х200 | 100Х200 | 100Х200 | 100Х200 | 100Х250 |
| 140 | 75Х125 | 75Х175 | 75Х200 | 75Х200 | 75Х200 | 100Х200 | 100Х200 |
| 110 | 75Х150 | 75Х150 | 75Х175 | 75Х175 | 75Х200 | 75Х200 | 100Х200 |
| 90 | 50Х150 | 50Х175 | 50Х200 | 75Х175 | 75Х175 | 75Х250 | 75Х200 |
| 60 | 40Х150 | 40Х175 | 50Х150 | 50Х150 | 50Х175 | 50Х200 | 50Х200 |
Let's give another table for those who will use hardwood lumber.
Table: maximum deviations from the nominal dimensions of the boards
We check the correctness of the calculations by substituting the numerical parameters into the following inequality / ≤ 1. We get (3.125 · 195 x 4.79³) / (7.5 x 25³) = 0.57 - the cross section is selected accurately and with a good margin. Let's check less powerful beams with a section of 50x250 mm. We substitute the values again: (3.125 · 195 x 4.79³) / (5 x 25³) = 0.86. The inequality is satisfied again, so a beam measuring 50x250 mm is quite suitable for our roof.
Video: calculation of the hip roof rafter system
After all the intermediate calculations, we summarize: to erect the roof we will need 117 linear meters of edged boards with a section of 50X250 mm. This is approximately 1.5 m³. Since it was initially agreed that for a four-slope hip design It is advisable to use lumber of the same section, then for the mauerlat you should purchase the same timber in an amount equal to the perimeter of the house - 7.5 2 + 12 2 = 39 linear meters. m. Taking into account a 10% reserve for cutting and scrap, we get 43 linear meters or approximately 0.54 m³. Thus, we will need approximately 2 m³ of lumber with a section of 50X250 mm.
The length of the rafters is the interval from the cut for the supporting part to the cut for the ridge beam.
Video: example of roof calculation using an online calculator
Rafter system installation technology
The arrangement of a hipped structure has its own characteristics that must be taken into account:
Manufactured and assembled in compliance with all the rules, a layered rafter frame for a hipped roof will be a non-thrust structure. You can prevent the appearance of thrusts if the planes of the rafters are made horizontal in places where they support the Mauerlat.
In most cases, two schemes are used to support the rafter legs.
In hip hip structures, the length of the corner legs is often longer than the typical length of the lumber. Therefore, the beams and boards are spliced, trying to place the joints at a distance of 0.15 span lengths (L) from the center of the supports, which is approximately equivalent to the interval between the support points. The rafters are connected using the oblique cutting method, tightening the joints with bolts Ø12–14 mm. It is recommended to make the cut on the rafters, and not on the support beam, so that the cut does not weaken the support.
Since the standard length of most lumber does not exceed 6 m, diagonal rafters are increased in length using the oblique cutting method and connected with bolts when using timber or with nails and clamps if boards are spliced
Table: position of supports for corner rafters
| Span length, m | Types of supports | Location of supports |
| less than 7.5 | stand or strut | at the top of the rafters |
| less than 9.0 | stand or strut | at the top of the rafters |
| truss or stand | at the bottom of the rafters - 1/4L inc. | |
| over 9.0 | stand or strut | at the top of the rafters at the bottom of the rafters - 1/4L pr |
| truss or stand | in the center of the rafters | |
| rack | in the center of the rafters | |
| Note: Lpr is the length of the span, which is covered by rafters. | ||
To connect the frames to the rafters, the top of the half-rafters is ground off, keeping them in the same plane as the corner legs, and secured with nails. When placing sprigs on the rafters, make sure that they do not converge in one place. If you use 50X50 mm cranial bars, packed in the lower zone of the rafters on both sides, rather than a notch when installing the rafters, then the rigidity of the rafter legs will be higher, which means their load-bearing capacity will increase.
To increase the rigidity of the rafter frame, it is recommended to use cranial bars stuffed on both sides at the bottom of the rafter legs when installing the rafters.
Do-it-yourself installation of a truss structure
The construction of the frame of a hipped roof is carried out in several stages.
- The materials are marked and calculated, after which roofing felt is laid as waterproofing along the entire perimeter of the building. A support for the racks and a Mauerlat are placed on top of it, securing it to the walls, fixing it especially well in the corners.
The Mauerlat in hipped structures is laid around the entire perimeter and is well secured to the walls, especially in the corners, to create a strong unit for attaching diagonal rafters
- Install the frame for the ridge girder and lay the girder itself, strictly maintaining the height and spatial arrangement ridge, since the strength and reliability of the entire rafter structure directly depends on this.
- Place the support posts using a water level for leveling and secure them under the ridge with inclined supports. The placement of racks is done based on the configuration of the roof - in a hip structure, the racks are installed in one row with an interval of no more than two meters, and in a hip roof - diagonally at the same interval from the corner.
- The central intermediate rafters are mounted, and then the ordinary ones, filling the middle of the side slopes.
- According to the markings, corner rafters are installed, preferably made with reinforcement, resting their lower part on the corner of the Mauerlat, and their upper fragment on the stand. The installation of the eaves overhang and drainage is also done here.
- Next, half-rafters (springs) are placed, strengthening the lower part of the diagonal legs with trusses, which will partially relieve the corner rafters, and they are sheathed along the perimeter of the roof with a wind board.
Truss grating is used for steep roofs and relatively large spans in order to avoid deflection of diagonal rafters
- After installation of the rafter system, the roofing pie is laid and arranged eaves overhangs and drainage system.
When installing the rafter system of a hipped roof, you need to carefully consider the joining of the diagonal rafters, the central rafter at the end of the building, as well as the ridge beam
Video: hipped roof on nails and stool
Self-construction a hipped roof is, of course, not an easy process. But if you have measuring instruments, as well as necessary tools, you will succeed. The main thing is the desire to assemble the structure with your own hands and the desire to adhere to general principles. And in order for the roof to last as long as possible and maintain its amazingly beautiful appearance, try not to skimp on the elements of the rafter frame and use modern reliable metal fasteners for wood to fix them.
The roof is no less important element of the house than the foundation and walls. Its design sets the mood for the entire architectural ensemble, making the building neat and attractive. The hipped roof has gained wide popularity not only because of its high reliability and external attractiveness, but also due to the opportunity to equip additional structures - attic and dormer windows, bay windows, etc. Despite the fact that the installation of such a roof is a little more expensive and more complicated than a gable structure, it is still easy to build it with your own hands.
Advantages of hip roofs over gable structures
One of the main tasks that appears even at the stage of designing your own home is choosing the type of roof. The presence of many options among gable and hipped structures requires an answer to the question of which roof to give preference to. And although the aesthetics of the structure plays an important role, the criteria of reliability and practicality still come to the fore.
A gable roof is a classic structure that is formed by two opposite slopes and a pair of vertical end parts called gables. The spacious under-roof space allows you to equip an attic, living space or use the attic for domestic purposes.
Classical gable roof easy to recognize by a pair of rectangular slopes that adjoin each other along the central axis of the building, and two triangular gables from its endsStructures of this type, due to their simplicity and practicality, remained the most popular in the world for a long time. individual construction. At the same time, the dependence of the roof geometry on the size of the building, as well as the complication and rise in cost of the structure when arranging the attic, forced the search for other, more practical and functional options. And they were found in the form of various hipped roofs, which are based on a pair of triangular and two trapezoidal slopes. The latter are often called hips, and the roof itself is called a hip roof. When erecting a structure of this type, there is no need for gables and it becomes possible to make the building more modern and original.
The slopes of the simplest hip roof define the surfaces in the form of two trapezoids and a pair of triangles There are several advantages of hip roofs over traditional gable structures:
- the possibility of installing attic windows directly on the slopes;
- increased strength, reliability and stability of the rafter system;
- increased resistance to weather factors;
- the possibility of increasing the area of the attic by simply reducing the width of the base of the hip;
- more uniform distribution of roof weight;
- improved temperature regime when arranging an attic room.
Don’t be fooled by the many advantages of a more stylish hipped roof - it also has disadvantages. These include a more complex design, a slight reduction in the size of the attic space and wasteful use of roofing material. As for expenses, the budget required for the construction of one and the other roof differs slightly.
The hipped roof is not a know-how in architecture - its design has been known since ancient times Classification of hip roofs
Differences in the shape of buildings, as well as the requirements for functionality and practicality of the traditional hip roof, have led to many variations. If we do not consider the most exotic of them, then we can distinguish several main types of hipped roofs.
- Traditional hip roof, the side slopes of which reach the eaves level. To construct its main surfaces, straight rafters are used, and the ribs of the hips form beams extending from the ends of the ridge. The elaborate design and distribution of the weight of the roof over a larger area allows not only to position the overhangs on the same line, but also to increase their reach. Thanks to this, the façade of the building is reliably protected from rain even in strong gusts of wind.
Glazing elements are often built into the slopes of a classic hip roof. - A hip roof can be installed on a house that has a square shape in plan. A feature of this design is the slopes of the same configuration. Their ribs converge at one point, and their hips have the shape isosceles triangles.
Hip roofs are widely used in modern individual construction - Half-hip roofs got their name because of the shortened hips. Unlike traditional roofing, their length is reduced by 1.5–3 times compared to the size of the main slopes.
The side slopes of half-hip roofs have a shortened length, so they do not reach the eaves line - The Danish half-hip roof has a small gable under the ridge and a short hip on the eaves side. This design allows you to install ventilation and lighting elements directly into the vertical end of the roof, thereby eliminating the need to install skylights.
The Danish project is good because it allows you to easily equip attic spaces - A half-hip Dutch roof has a vertical gable that divides the hip into two short slopes. Rafter system"Dutch" although it has increased complexity, but it allows you to make the attic space more spacious and practical. In addition, this design is excellent for installing vertical glazing in the attic.
A roof built according to a Dutch design is still rare in our area. - A sloping hip roof has several slopes of different sizes on one slope. Thanks to their different slopes, it is possible to increase the volume of the under-roof space. Although a broken structure cannot be called simple, houses with such a roof are very common. The reason for its popularity is the opportunity to arrange additional living rooms on the upper tier. For this reason, a roof with broken slopes is often called an attic roof.
The sloping roof makes the architecture of the building somewhat heavier, but it makes it possible to arrange several living spaces in the attic space
There are also more complex structures consisting of many hips, as well as those in which a hip roof is combined with roofing systems other types. The design and installation of such a roof requires many years of experience and knowledge, so it is better to entrust the construction of a sophisticated roof to specialists.
Design of hip roofs
When developing a hip roof, all types of loads that will affect it are taken into account. To do this, you must first resolve several important issues:
- purpose of the attic space;
- roofing material;
- degree of atmospheric influence in the construction region.
Based on these factors, the degree of slope of the slopes and the roof area are determined, the loads are calculated and a decision is made on the design and parameters of the rafter system.
Geometric parameters of slopes
The angle of inclination of the slopes depends on the snow and wind load, therefore it varies within a very wide range - from 5 to 60 degrees. In areas with rainy weather and high snow cover, roofs with a slope of 45 to 60 degrees are erected. If the region is different strong winds and a minimum amount of precipitation, then the slope can be reduced to the very minimum.
When determining the angular parameters of the roof, it is necessary to take into account what material it will be covered with:
- slate sheets, ondulin, roofing metal and rolled materials are laid on slopes with a slope of 14 to 60 degrees;
- the tiles are mounted on a surface with a degree of slope from 30 to 60 degrees;
- Roll coating is used on sloping slopes - from 5 to 18 degrees.
Having decided on the angle of the roof, it is not at all difficult to calculate at what height the ridge will be. To do this, use simple trigonometric formulas for a right triangle.
Roof area
Even the most complex hip roof consists of individual slopes that follow the contours of the simplest geometric shapes, therefore, most often for calculations it is enough to know the linear dimensions of the base and the angles of inclination of the hips.
To determine the square footage of the roof, it is necessary to add up the areas of the slopes of which it consists The total roof area is calculated by summing the square footage of the individual hips. Slopes of complex configuration are divided into several simple surfaces, after which separate calculations are carried out for each of them.
The principles for calculating the geometric parameters of hip roofs are based on calculations for simple surfaces Load calculation
Loads acting on a hipped roof are divided into two types:
- permanent,
- periodic.
The first includes the weight of roofing materials, rafters, sheathing and other frame parts. The second is the forces exerted by precipitation and wind force. In addition, the calculation should take into account the payload in the form of various engineering systems and communications attached to the elements of the rafter system.
Based on SNiP, when designing a roof it is necessary to take snow load 180 kg/sq. m. If there is a danger of snow accumulation on the roof, this parameter increases to 400–450 kg/sq. m. If the roof has a slope angle of more than 60 degrees, then the snow load can be ignored - precipitation does not linger on surfaces with such steep slopes.
The force of wind loads is much less - up to 35 kg/sq. m. If the roof slope is from 5 to 30 degrees, then the effect of the wind can be neglected.
The above parameters atmospheric influences are average values accepted for middle zone. When performing calculations, correction factors should be used depending on the region of construction.
Calculation of the rafter system
When calculating the rafter system, the pitch of the rafters and the maximum load they can carry are determined. Based on these data, a decision is made to install braces, which help redistribute the load, and tie-downs, which protect the frame from loosening.
The main load of the hip roof falls on the diagonal rafters The presence of hips on hipped roofs, in addition to the usual rafters, also requires the installation of diagonal rafters (in other words, slanted ones) - those that are attached to the ridge and directed to the corners of the building. Their length is greater than the transverse node elements of the roof. In addition, shortened elements - sprigs - are attached to the diagonal ribs. Compared to conventional rafters, slanted legs experience a load increased by 1.5–2 times, so their cross-section is doubled, and to ensure multi-span they are supported by one or two racks.
Often, hip roofs have a complicated rafter system, which, in contrast to a simple hipped structure, places additional load where vertical supports are installed. This feature must be taken into account when calculating the strength of a wooden roof frame.
The laying distance of the rafters is called the pitch and is determined based on the length of the rafter leg and the cross-section of the lumber used. It is most convenient to determine this parameter using special tables, one of which is given below.
Table: dependence of the cross-section and pitch of rafters on their length
Manual calculations are quite labor-intensive. To reduce design time, you can use one of the online calculators to determine the parameters of hip roofs. With its help, you can determine not only geometric parameters, but also a lot of others no less important factors:
- amount of moisture and heat insulation, taking into account overlaps;
- amount of roofing material, including waste generated during cutting;
- the volume of lumber required for arranging the rafter system;
- length of overhangs, etc.
Video: using a construction calculator to calculate a roof
What materials will be needed to assemble the rafter system?
For the construction of a hip roof, timber and boards made of larch, pine and other wood are best suited coniferous species. When choosing material for construction, it is necessary to carefully reject defective boards. Fungal damage, knots and cracks reduce the strength of the boards and affect the durability of the roof. When the wood moisture content is more than 22%, the lumber is stacked in the open air and dried. It should be understood that under-dried boards can warp, and this, in turn, will lead to a violation of the roof geometry with possible damage finishing coating.
To assemble a wooden frame, a rectangular beam with a cross-section from 80x80 mm to 150x150 mm is used - the exact parameters are determined by calculation or using the table above. As an alternative, you can use a board with a section of 50x100 mm or 50x200 mm. If there is a need to strengthen the rafter leg, then paired boards are used.
For reliable fastening, as well as increasing the rigidity of the wooden frame, steel brackets and other metal elements are used. Often, under especially loaded ridge girders, they install not wooden, but steel supports. Combined frames have increased strength and reliability.
Features of the rafter system
In order to correctly design and install a hip roof, it is necessary to understand in detail its design, as well as the design features of the most common types of hip roofs.
The structure of the rafter system in detail
The frame of a hip roof consists of most of the same parts as a gable roof, but a more complex rafter system requires the installation of additional elements. Upon closer examination, the following components can be found:
All these elements can be found in any type of hip roof. The only exception is hip roof, which does not have side rafters and ridge beams.
In wooden and frame houses, the rafter system is installed without a Mauerlat. In the first case, its functions are taken over by the outer crowns, and in the second - by the upper trim.
Types of rafter systems for hip roofs
Since the basis of the hip roof rafter system is made up of slanted rafters, during installation roof frame the following rules must be adhered to:
- In structures where the slanted legs experience increased load, timber of double thickness is used for their manufacture.
- The splicing of individual parts of diagonal rafters is carried out in places with maximum load (most often in their upper part) and strengthened with the help of struts and vertical posts installed at an angle of 90° to the rafter legs.
- When making slanted rafters, allowance should be made for local trimming, therefore effective length timber is increased by 5–10%.
- Critical connection points of slanted rafter legs must be reinforced with metal fasteners - staples, twists or perforated construction strips.
When choosing a rafter system, it is necessary to take into account the size of the building and the presence of internal supports or permanent walls. Based on specific conditions, a scheme with hanging or layered rafters is chosen.
Hanging rafter system
The roof structure with hanging rafters has no supports midline, so the main weight falls on the outer perimeter walls. This feature manifests itself in the redistribution of internal forces - the rafter system is subjected to compressive and bending loads. As for the walls, significant pushing forces are transmitted to them. To eliminate this factor, each pair of rafters is connected to each other by so-called ties - jumpers made of wooden beams or rolled metal.
The tie can be located either at the base of the rafter legs or above. In the first case, the jumper will also play the role of cross beam, which is a good option for construction mansard roof. If the tightening is installed in the area of the midline or above, then it will only serve as a fastening link. It should be noted that the cost of the rafter system depends on such a seemingly insignificant moment as the installation height of the tie rods. The higher they are located crossbars, the larger the cross-section of all components of the wooden frame should be.
Hip roofs with layered and hanging rafters have differences between the supporting elements of the structure Construction with layered rafters
A hip roof with layered rafters is suitable only for those houses whose internal space is divided into two equal parts by a main wall or installed to support the ceiling support pillars. In this case, the lower edge of the rafter legs rests on the Mauerlat, and middle part- on the load-bearing wall. The presence of additional support points allows you to relieve the elements of the rafter system by removing alternating horizontal forces from them, as well as from the walls of the building. Like roof beams, rafters begin to work only in bending. A frame with layered rafters becomes more rigid and durable compared to a structure that uses unsupported rafters. And this despite the fact that in the first case you can use timber of a smaller cross-section. And this helps reduce the weight of the wooden structure and reduces the cost of purchasing lumber.
Installation of a hip roof
The assembly of the rafter system must be carried out in a strictly defined order. This is necessary in order to correctly install and secure all structural elements of the roof.
- To redistribute the load exerted on the walls by the roofing structure, wind and precipitation, a Mauerlat is laid on the external walls. In individual construction, timber with a cross-section of at least 100x150 mm is used for these purposes. Anchor pins are used to secure the longitudinal beams of the structure. They must be laid in the upper rows of the masonry at the stage of wall construction. Waterproofing of the Mauerlat is carried out using two layers of roofing material, which is laid on top of the load-bearing walls.
The Mauerlat is attached to the load-bearing wall using bolts or anchors - If it is necessary to install vertical supports, beds are laid on the load-bearing walls. Wooden pads are used to horizontally level the elements of the rafter system. In the future, this will greatly simplify the installation of racks and purlins. If capital partitions are not provided for in the building plan, then vertical supports are mounted on floor beams. To do this, they are strengthened by joining two 50x200 mm boards or using one 100x200 mm beam.
Support of vertical posts on beams is allowed only if the structure rests on a permanent pier - Set up support posts. To level them, use a plumb line or laser level, after which temporary supports are installed. For fastening vertical support metal corners and plates are used to the bench or horizontal beam.
- Purlins are laid on top of the racks. A traditional hip roof requires the installation of one purlin, which, in fact, forms the ridge. Tent structures require the installation of four purlins. As with the installation of racks, fastening is carried out using metal corners and self-tapping screws.
The ridge purlin can be attached either directly to the rafter leg or using wooden plates - Preparing the rafters. The side rafters of simple hipped roofs are mounted in the same way as the sloping ones on gable roof. First you need to make a template. To do this, from the side of the outer support, apply a board of the same width as the rafters to the ridge. Its thickness should not exceed 25 mm - the template should be light. On this board, a notch is noted, which is necessary for reliable support and precise fit of the rafter leg to the ridge beam, as well as a cutout corresponding to the junction with the Mauerlat. The marked areas are cut out and then used for quick preparation of the rafter legs.
Making a template can reduce the time it takes to prepare rafters for installation - By applying the manufactured sample to the purlin, it is necessary to check whether precise adjustment of the rafters is necessary. If there are gaps, cuts in the rafters are made taking into account the amendments. After all the supporting legs are ready, they are set in increments of 50–150 cm and attached to the Mauerlat and the ridge. For installation, staples are best suited, but you can also use strong metal corners.
- As already mentioned, diagonal rafters are made from spliced boards or timber of increased cross-section. To install them, you will also need a template, which is prepared in full accordance with the method described above. Since the slanted rafters are adjacent to the corner of the mauerlat on one side, and rest on the racks on the other, the cut is made at an angle of 45° to the plane.
The layout of rafters and soffits on a hip roof is carried out according to a template - In the gaps between the sloped rafters, sprigs are attached. Their step corresponds to the distance between the rafters, and the diagonal legs and the mauerlat act as support points. The load experienced by the rafters cannot be compared with the weight that falls on the rafters, so the former can be constructed from boards 30–50 mm thick. To speed up installation, you will need a template with notches on the side of the diagonal rafters and the mauerlat, but the cutouts on half of the frames must be made in a mirror image.
Use of metal fastening elements makes the rafter system more rigid and stable - If there is a need, fillies are attached to the rafters and frames. The ends of the rafter elements are cut along the cord.
Attaching the rafters to the Mauerlat can be done in several ways - Strengthen the slopes and side rafters. In the first case, vertical trusses are used, and in the second, struts installed at an angle of 45° are used. They are supported on beds or beams.
- After the rafter system is assembled, a roofing pie is installed on top of it.
The rafter system is prepared for installation of roofing materials
Lathing and insulation
Before proceeding with the installation of the sheathing, a vapor barrier and, if necessary, rolled thermal insulation are laid on top of the rafters. The top layer of insulation is covered waterproofing film, which is mounted with an overlap of 10–20 mm wide and secured to the beam with a construction stapler. After this, counter battens are nailed to the rafters. If the roofing pie is installed without insulation, then a vapor barrier is not required - a layer of moisture-resistant material will be sufficient. Of course, additional slats will not be needed in this case, since the boards supporting the roof will be attached directly to the frames and rafter legs.
Depending on the type of roofing material, one of two types of sheathing is used on hip roofs:
- continuous;
- sparse.
The first is most often equipped for a soft roof and only in some cases - for arranging an attic space. This type of lathing is made from boards with a width of 100 to 200 mm and a thickness of at least 20–25 mm. Installation is carried out without gaps. In addition, it is possible to use plywood sheets and OSB boards. Their dignity is extremely flat surface, which allows you to lay roofing material With minimal costs time and effort.
Under a soft roof they equip continuous sheathing from OSB, plywood or boards packed without gaps For sparse sheathing, use the same boards as in the first case, but install them with a gap. Since this type of base is used for laying slate, corrugated sheets, metal tiles and roofing iron, the distance between individual boards must take into account the characteristics of the roofing material.
The sheathing is fastened with nails, the length of which is equal to triple the thickness of the boards. If self-tapping screws are used for fixation, then you can use a shorter threaded fastener with a length corresponding to double the thickness of the lumber.
For fastening slate, ondulin and others sheet materials use sparse lathing Wooden base The roofing pie is mounted from the bottom up, with the first board of each slope being aligned parallel to the Mauerlat. First, the sheathing is stuffed on the hips, after which the protruding edges are cut off with a hacksaw flush with the diagonal ribs. Next, they begin to fasten the lumber on the main slopes, releasing the edges of the boards beyond the sloped rafters. After this, the ends of the boards are sawed down similarly to the first case.
Video: building a hip roof with your own hands
Typical hip roof design
When building a simple hip roof, you can use a standard project developed by specialists. Project documentation includes:
- technological map;
- roof plan;
- rafter system diagrams;
- drawings of sections and corner connections;
- statement and specification with a complete list of materials used.
As a sample, below is documentation for a typical hip roof design for a house with an area of 155 square meters. m.
Gallery: drawings and diagrams of a hipped roof
The drawing indicates the exact dimensions of all roof elements. Triangles lie at the base of the rafter truss. Rafters of trapezoidal slopes rest on the long load-bearing walls of the building. Tie-rods are installed at the base of the rafters and act as floor beams. When creating a project, it is necessary to take into account the length of the rafters, their pitch, the recommended cross-section of the beam or board. rafter fastenings are made of wood and hardware Fastenings allow you to transfer the load from one element of the system to another
Despite the apparent complexity of a hipped roof, building it with your own hands is not much more difficult than gable structure. It is only important to carefully understand the purpose of the individual elements and the principles of constructing the rafter system. Otherwise, the reliability and durability of the roof will still depend on adherence to technology and careful installation. As for the additional difficulties and costs, they will be repaid with complete satisfaction from the work, which will make the building brighter and more attractive.
The roof is no less important element of the house than the foundation and walls. Its design sets the mood for the entire architectural ensemble, making the building neat and attractive. The hipped roof has gained wide popularity not only because of its high reliability and external attractiveness, but also due to the opportunity to equip additional structures - attic and dormer windows, bay windows, etc. Despite the fact that the installation of such a roof is a little more expensive and more complex than a gable structure , it is still easy to build it with your own hands.
Advantages of hip roofs over gable structures
One of the main tasks that appears even at the stage of designing your own home is choosing the type of roof. The presence of many options among gable and hipped structures requires an answer to the question of which roof to give preference to. And although the aesthetics of the structure plays an important role, the criteria of reliability and practicality still come to the fore.
A gable roof is a classic structure that is formed by two opposite slopes and a pair of vertical end parts called gables. The spacious under-roof space allows you to equip an attic, living space or use the attic for domestic purposes.
The classic gable roof is easily recognized by a pair of rectangular slopes that adjoin each other along the central axis of the building, and two triangular gables at its ends
Structures of this type, due to their simplicity and practicality, remained the most popular in individual construction for a long time. At the same time, the dependence of the roof geometry on the size of the building, as well as the complication and rise in cost of the structure when arranging the attic, forced the search for other, more practical and functional options. And they were found in the form of various hipped roofs, which are based on a pair of triangular and two trapezoidal slopes. The latter are often called hips, and the roof itself is called a hip roof. When erecting a structure of this type, there is no need for gables and it becomes possible to make the building more modern and original.
The slopes of the simplest hip roof define the surfaces in the form of two trapezoids and a pair of triangles
There are several advantages of hip roofs over traditional gable structures:
- the possibility of installing attic windows directly on the slopes;
- increased strength, reliability and stability of the rafter system;
- increased resistance to weather factors;
- the possibility of increasing the area of the attic by simply reducing the width of the base of the hip;
- more uniform distribution of roof weight;
- improved temperature conditions when arranging the attic space.
Don’t be fooled by the many advantages of a more stylish hipped roof - it also has disadvantages. These include a more complex design, a slight reduction in the size of the attic space and wasteful use of roofing material. As for expenses, the budget required for the construction of one and the other roof differs slightly.
The hipped roof is not a know-how in architecture - its design has been known since ancient times
Classification of hip roofs
Differences in the shape of buildings, as well as the requirements for functionality and practicality of the traditional hip roof, have led to many variations. If we do not consider the most exotic of them, then we can distinguish several main types of hipped roofs.
- Traditional hip roof, the side slopes of which reach the eaves level. To construct its main surfaces, straight rafters are used, and the ribs of the hips form beams extending from the ends of the ridge. The elaborate design and distribution of the weight of the roof over a larger area allows not only to position the overhangs on the same line, but also to increase their reach. Thanks to this, the façade of the building is reliably protected from rain even in strong gusts of wind.
Glazing elements are often built into the slopes of a classic hip roof.
- A hip roof can be installed on a house that has a square shape in plan. A feature of this design is the slopes of the same configuration. Their ribs converge at one point, and their hips have the shape of isosceles triangles.
Hip roofs are widely used in modern individual construction
- Half-hip roofs got their name because of the shortened hips. Unlike traditional roofing, their length is reduced by 1.5–3 times compared to the size of the main slopes.
The side slopes of half-hip roofs have a shortened length, so they do not reach the eaves line
- The Danish half-hip roof has a small gable under the ridge and a short hip on the eaves side. This design allows you to install ventilation and lighting elements directly into the vertical end of the roof, thereby eliminating the need to install skylights.
The Danish project is good because it allows you to easily equip attic spaces
- A half-hip Dutch roof has a vertical gable that divides the hip into two short slopes. Although the “Dutch” rafter system has increased complexity, it allows you to make the attic space more spacious and practical. In addition, this design is excellent for installing vertical glazing in the attic.
A roof built according to a Dutch design is still rare in our area.
- A sloping hip roof has several slopes of different sizes on one slope. Thanks to their different slopes, it is possible to increase the volume of the under-roof space. Although a broken structure cannot be called simple, houses with such a roof are very common. The reason for its popularity is the opportunity to arrange additional living rooms on the upper tier. For this reason, a roof with broken slopes is often called an attic roof.
The sloping roof makes the architecture of the building somewhat heavier, but it makes it possible to arrange several living spaces in the attic space
There are also more complex structures consisting of many hips, as well as those in which a hipped roof is combined with other types of roofing systems. The design and installation of such a roof requires many years of experience and knowledge, so it is better to entrust the construction of a sophisticated roof to specialists.
Design of hip roofs
When developing a hip roof, all types of loads that will affect it are taken into account. To do this, you must first resolve several important issues:
- purpose of the attic space;
- roofing material;
- degree of atmospheric influence in the construction region.
Based on these factors, the degree of slope of the slopes and the roof area are determined, the loads are calculated and a decision is made on the design and parameters of the rafter system.
Geometric parameters of slopes
The angle of inclination of the slopes depends on the snow and wind load, therefore it varies within a very wide range - from 5 to 60 degrees. In areas with rainy weather and high snow cover, roofs with a slope of 45 to 60 degrees are erected. If the region is characterized by strong winds and minimal precipitation, then the slope can be reduced to the very minimum.
When determining the angular parameters of the roof, it is necessary to take into account what material it will be covered with:
- slate sheets, ondulin, roofing metal and rolled materials are laid on slopes with a slope of 14 to 60 degrees;
- the tiles are mounted on a surface with a degree of slope from 30 to 60 degrees;
- Roll coating is used on sloping slopes - from 5 to 18 degrees.
Having decided on the angle of the roof, it is not at all difficult to calculate at what height the ridge will be. To do this, use simple trigonometric formulas for a right triangle.
Roof area
Even the most complex hip roof consists of individual slopes that follow the contours of the simplest geometric shapes, so most often for calculations it is enough to know the linear dimensions of the base and the angles of inclination of the hips.
To determine the square footage of the roof, it is necessary to add up the areas of the slopes of which it consists
The total roof area is calculated by summing the square footage of the individual hips. Slopes of complex configuration are divided into several simple surfaces, after which separate calculations are carried out for each of them.
The principles for calculating the geometric parameters of hip roofs are based on calculations for simple surfaces
Load calculation
Loads acting on a hipped roof are divided into two types:
- permanent,
- periodic.
The first includes the weight of roofing materials, rafters, sheathing and other frame parts. The second is the forces exerted by precipitation and wind force. In addition, when calculating, one should take into account the payload in the form of various engineering systems and communications attached to the elements of the rafter system.
Based on SNiP, when designing a roof it is necessary to assume a snow load of 180 kg/sq. m. If there is a danger of snow accumulation on the roof, this parameter increases to 400–450 kg/sq. m. If the roof has a slope angle of more than 60 degrees, then the snow load can be ignored - precipitation does not linger on surfaces with such steep slopes.
The force of wind loads is much less - up to 35 kg/sq. m. If the roof slope is from 5 to 30 degrees, then the effect of the wind can be neglected.
The above parameters of atmospheric influences are average values accepted for the middle zone. When performing calculations, correction factors should be used depending on the region of construction.
Calculation of the rafter system
When calculating the rafter system, the pitch of the rafters and the maximum load they can carry are determined. Based on these data, a decision is made to install braces, which help redistribute the load, and tie-downs, which protect the frame from loosening.
The main load of the hip roof falls on the diagonal rafters
The presence of hips on hipped roofs, in addition to the usual rafters, also requires the installation of diagonal rafters (in other words, slanted ones) - those that are attached to the ridge and directed to the corners of the building. Their length is greater than the transverse node elements of the roof. In addition, shortened elements - sprigs - are attached to the diagonal ribs. Compared to conventional rafters, slanted legs experience a load increased by 1.5–2 times, so their cross-section is doubled, and to ensure multi-span they are supported by one or two racks.
Often, hip roofs have a complicated rafter system, which, in contrast to a simple hipped structure, places additional load where vertical supports are installed. This feature must be taken into account when calculating the strength of a wooden roof frame.
The laying distance of the rafters is called the pitch and is determined based on the length of the rafter leg and the cross-section of the lumber used. It is most convenient to determine this parameter using special tables, one of which is given below.
Table: dependence of the cross-section and pitch of rafters on their length
Manual calculations are quite labor-intensive. To reduce design time, you can use one of the online calculators to determine the parameters of hip roofs. With its help, you can determine not only geometric parameters, but also a lot of other equally important factors:
- amount of moisture and heat insulation, taking into account overlaps;
- amount of roofing material, including waste generated during cutting;
- the volume of lumber required for arranging the rafter system;
- length of overhangs, etc.
Video: using a construction calculator to calculate a roof
What materials will be needed to assemble the rafter system?
For the construction of a hip roof, timber and boards made of larch, pine and other coniferous wood are best suited. When choosing material for construction, it is necessary to carefully reject defective boards. Fungal damage, knots and cracks reduce the strength of the boards and affect the durability of the roof. When the wood moisture content is more than 22%, the lumber is stacked in the open air and dried. It should be understood that under-dried boards may warp, and this, in turn, will lead to a violation of the geometry of the roof with possible damage to the finishing coating.
To assemble a wooden frame, a rectangular beam with a cross-section from 80x80 mm to 150x150 mm is used - the exact parameters are determined by calculation or using the table above. As an alternative, you can use a board with a section of 50x100 mm or 50x200 mm. If there is a need to strengthen the rafter leg, then paired boards are used.
For reliable fastening, as well as increasing the rigidity of the wooden frame, steel brackets and other metal elements are used. Often, steel supports, rather than wooden ones, are installed under particularly loaded ridge girders. Combined frames have increased strength and reliability.
Features of the rafter system
In order to correctly design and install a hip roof, it is necessary to understand in detail its design, as well as the design features of the most common types of hip roofs.
The structure of the rafter system in detail
The frame of a hip roof consists of most of the same parts as a gable roof, but a more complex rafter system requires the installation of additional elements. Upon closer examination, the following components can be found:
All these elements can be found in any type of hip roof. The only exception is the hip roof, which does not have side rafters or ridge beams.
In wooden and frame houses, the rafter system is installed without a Mauerlat. In the first case, its functions are taken over by the outer crowns, and in the second - by the upper trim.
Types of rafter systems for hip roofs
Since the basis of the hip roof rafter system is made up of slanted rafters, when installing the roof frame, you must adhere to the following rules:
- In structures where the slanted legs experience increased load, timber of double thickness is used for their manufacture.
- The splicing of individual parts of diagonal rafters is carried out in places with maximum load (most often in their upper part) and strengthened with the help of struts and vertical posts installed at an angle of 90° to the rafter legs.
- When making slanted rafters, allowance should be made for local trimming, so the estimated length of the beam is increased by 5–10%.
- Critical connection points of slanted rafter legs must be reinforced with metal fasteners - staples, twists or perforated construction strips.
When choosing a rafter system, it is necessary to take into account the size of the building and the presence of internal supports or permanent walls. Based on specific conditions, a scheme with hanging or layered rafters is chosen.
Hanging rafter system
A hanging rafter roof structure has no centerline supports, so the bulk of the weight falls on the outer perimeter walls. This feature manifests itself in the redistribution of internal forces - the rafter system is subjected to compressive and bending loads. As for the walls, significant pushing forces are transmitted to them. To eliminate this factor, each pair of rafters is connected to each other by so-called ties - jumpers made of wooden beams or rolled metal.
The tie can be located either at the base of the rafter legs or above. In the first case, the lintel will also act as a transverse beam, which is a good option when constructing an attic roof. If the tightening is installed in the area of the midline or above, then it will only serve as a fastening link. It should be noted that the cost of the rafter system depends on such a seemingly insignificant moment as the installation height of the tie rods. The higher the cross-lintels are located, the larger the cross-section of all components of the wooden frame should be.
Hip roofs with layered and hanging rafters have differences between the supporting elements of the structure
Construction with layered rafters
A hip roof with layered rafters is suitable only for those houses whose interior space is divided into two equal parts by a main wall or support pillars installed to support the ceiling. In this case, the lower edge of the rafter legs rests on the mauerlat, and the middle part rests on the load-bearing partition. The presence of additional support points allows you to relieve the elements of the rafter system by removing alternating horizontal forces from them, as well as from the walls of the building. Like roof beams, rafters begin to work only in bending. A frame with layered rafters becomes more rigid and durable compared to a structure that uses unsupported rafters. And this despite the fact that in the first case you can use timber of a smaller cross-section. And this helps reduce the weight of the wooden structure and reduces the cost of purchasing lumber.
Installation of a hip roof
The assembly of the rafter system must be carried out in a strictly defined order. This is necessary in order to correctly install and secure all structural elements of the roof.
- To redistribute the load exerted on the walls by the roofing structure, wind and precipitation, a Mauerlat is laid on the external walls. In individual construction, timber with a cross-section of at least 100x150 mm is used for these purposes. Anchor pins are used to secure the longitudinal beams of the structure. They must be laid in the upper rows of the masonry at the stage of wall construction. Waterproofing of the Mauerlat is carried out using two layers of roofing material, which is laid on top of the load-bearing walls.
The Mauerlat is attached to the load-bearing wall using bolts or anchors
- If it is necessary to install vertical supports, beds are laid on the load-bearing walls. Wooden pads are used to horizontally level the elements of the rafter system. In the future, this will greatly simplify the installation of racks and purlins. If capital partitions are not provided for in the building plan, then vertical supports are mounted on floor beams. To do this, they are strengthened by joining two 50x200 mm boards or using one 100x200 mm beam.
Support of vertical posts on beams is allowed only if the structure rests on a permanent pier
- Set up support posts. To level them, use a plumb line or laser level, after which temporary supports are installed. Metal angles and plates are used to attach the vertical support to the beam or horizontal beam.
- Purlins are laid on top of the racks. A traditional hip roof requires the installation of one purlin, which, in fact, forms the ridge. Tent structures require the installation of four purlins. As with the installation of racks, fastening is carried out using metal corners and self-tapping screws.
The ridge purlin can be attached either directly to the rafter leg or using wooden plates
- Preparing the rafters. The side rafters of simple hipped roofs are mounted in exactly the same way as the rafters on a gable roof. First you need to make a template. To do this, from the side of the outer support, apply a board of the same width as the rafters to the ridge. Its thickness should not exceed 25 mm - the template should be light. On this board, a notch is noted, which is necessary for reliable support and precise fit of the rafter leg to the ridge beam, as well as a cutout corresponding to the junction with the Mauerlat. The marked areas are cut out and then used for quick preparation of the rafter legs.
Making a template can reduce the time it takes to prepare rafters for installation
- By applying the manufactured sample to the purlin, it is necessary to check whether precise adjustment of the rafters is necessary. If there are gaps, cuts in the rafters are made taking into account the amendments. After all the supporting legs are ready, they are set in increments of 50–150 cm and attached to the Mauerlat and the ridge. For installation, staples are best suited, but you can also use strong metal corners.
- As already mentioned, diagonal rafters are made from spliced boards or timber of increased cross-section. To install them, you will also need a template, which is prepared in full accordance with the method described above. Since the slanted rafters are adjacent to the corner of the mauerlat on one side, and rest on the racks on the other, the cut is made at an angle of 45° to the plane.
The layout of rafters and soffits on a hip roof is carried out according to a template
- In the gaps between the sloped rafters, sprigs are attached. Their step corresponds to the distance between the rafters, and the diagonal legs and the mauerlat act as support points. The load experienced by the rafters cannot be compared with the weight that falls on the rafters, so the former can be constructed from boards 30–50 mm thick. To speed up installation, you will need a template with notches on the side of the diagonal rafters and the mauerlat, but the cutouts on half of the frames must be made in a mirror image.
The use of metal fasteners makes the rafter system more rigid and stable
- If there is a need, fillies are attached to the rafters and frames. The ends of the rafter elements are cut along the cord.
Attaching the rafters to the Mauerlat can be done in several ways
- Strengthen the slopes and side rafters. In the first case, vertical trusses are used, and in the second, struts installed at an angle of 45° are used. They are supported on beds or beams.
- After the rafter system is assembled, a roofing pie is installed on top of it.
The rafter system is prepared for installation of roofing materials
Lathing and insulation
Before proceeding with the installation of the sheathing, a vapor barrier and, if necessary, rolled thermal insulation are laid on top of the rafters. The top layer of insulation is covered with a waterproofing film, which is mounted with an overlap of 10–20 mm wide and secured to the beam with a construction stapler. After this, counter battens are nailed to the rafters. If the roofing pie is installed without insulation, then a vapor barrier is not required - a layer of moisture-resistant material will be sufficient. Of course, additional slats will not be needed in this case, since the boards supporting the roof will be attached directly to the frames and rafter legs.
Depending on the type of roofing material, one of two types of sheathing is used on hip roofs:
- continuous;
- sparse.
The first is most often equipped for a soft roof and only in some cases - for arranging an attic space. This type of lathing is made from boards with a width of 100 to 200 mm and a thickness of at least 20–25 mm. Installation is carried out without gaps. In addition, the use of plywood sheets and OSB boards is allowed. Their advantage is an extremely flat surface, which allows you to lay roofing material with minimal time and effort.
Under the soft roof, a continuous sheathing of OSB, plywood or boards packed without a gap is installed
For sparse sheathing, use the same boards as in the first case, but install them with a gap. Since this type of base is used for laying slate, corrugated sheets, metal tiles and roofing iron, the distance between individual boards must take into account the characteristics of the roofing material.
The sheathing is fastened with nails, the length of which is equal to triple the thickness of the boards. If self-tapping screws are used for fixation, then you can use a shorter threaded fastener with a length corresponding to double the thickness of the lumber.
To fasten slate, ondulin and other sheet materials, use sparse lathing
The wooden base of the roofing pie is mounted from the bottom up, with the first board of each slope aligned parallel to the mauerlat. First, the sheathing is stuffed on the hips, after which the protruding edges are cut off with a hacksaw flush with the diagonal ribs. Next, they begin to fasten the lumber on the main slopes, releasing the edges of the boards beyond the sloped rafters. After this, the ends of the boards are sawed down similarly to the first case.
Video: building a hip roof with your own hands
Typical hip roof design
When building a simple hip roof, you can use a standard project developed by specialists. Project documentation includes:
- technological map;
- roof plan;
- rafter system diagrams;
- drawings of sections and corner connections;
- statement and specification with a complete list of materials used.
As a sample, below is documentation for a typical hip roof design for a house with an area of 155 square meters. m.
Gallery: drawings and diagrams of a hipped roof
The drawing indicates the exact dimensions of all roof elements. Triangles lie at the base of the rafter truss. Rafters of trapezoidal slopes rest on the long load-bearing walls of the building. Tie-rods are installed at the base of the rafters and act as floor beams. When creating a project, it is necessary to take into account the length of the rafters, their pitch, the recommended cross-section of the beam or board. rafter fastenings use wooden and metal products. Fastenings allow you to transfer the load from one element of the system to another
Despite the apparent complexity of a hipped roof, building it with your own hands is not much more difficult than a gable structure. It is only important to carefully understand the purpose of the individual elements and the principles of constructing the rafter system. Otherwise, the reliability and durability of the roof will still depend on adherence to technology and careful installation. As for the additional difficulties and costs, they will be repaid with complete satisfaction from the work, which will make the building brighter and more attractive.
