Construction of a hip roof truss system: main structural elements. Construction of a hip roof: from frame to roofing Diagonal roof supports

A hip roof is one of the types of hipped roofs; its design includes two main trapezoidal and two end triangular slopes, forming a closed surface with a common ridge girder. If the side slopes are located over the entire area from the ridge to the eaves, then the roof is called hip, and if they do not reach the eaves - half-hip.

Types of rafter structures for hip roofs

If the rafter structure rests only on the main walls of the building, it is called hanging, and if it has additional support points due to the walls inside the house, then it is called layered.

If the rafter system rests only on the external load-bearing walls of the building, it is called hanging

If the building has two main walls, then a tension beam is laid at the top of the vertical posts, which strengthens the rafters and distributes the load over the entire area of the vertical support posts.

To create a hip roof, a layered rafter system is most suitable, since it has a greater degree of strength and makes it possible to lighten the roof structure, evenly distributing its weight over the entire building frame.

Rafter system hip roof may have several different installation methods, each of which requires the presence of certain features during assembly.

Traditional rafter system. In this design, the diagonal ribs rest on the main ridge support beam, and the overhangs are at the same height. This system consists of two isosceles triangles and two trapezoids.
The rafter system of a classic hip roof consists of two triangles and two trapezoids
Tent system. This design does not provide for the presence of a supporting ridge beam, because it is installed above square-shaped buildings and consists of four identical triangular slopes. All diagonal edges converge at common point, and short spigots are connected to them. Only professionals can make a reliable ridge unit for a hip roof.
The hip rafter system consists of four triangular slopes, converging at their upper parts to one point
Half hip design. This system provides for the presence of vertical parts in the gable slopes, into which standard windows can be installed.
The half-hip roof has vertical sections of gables into which ordinary windows can be inserted
Broken roof (attic). This is the most complex and labor-intensive hip roofing system, since all slopes have different shapes and areas and diverge from each other at different angles. Such a roof allows you to make the most efficient use of the area under the roof and create additional living quarters on it.
Broken or attic structure roof allows you to equip full-fledged living quarters in the under-roof space

How to calculate a rafter system for a hip roof

When calculating the design of hip roof rafters, the following factors must be taken into account.

Degree of regional wind load. The larger it is, the smaller the roof slope angle should be and the stronger the system. The main supporting rafters must be made of thick timber.
Amount of precipitation. The more precipitation falls annually, the steeper the roof slopes should be in order to avoid large pressure on the rafter structure.
Material for covering the roof of a house. Depending on the type and weight used roofing material a lathing system is selected. This factor is taken into account at the development stage of the house project.
Thermal insulation of the roof. The width of the insulation, the type and thickness of the timber are taken into account when calculating the installation pitch of the rafters.
Roof inclination angle. The slope of the roof affects the choice of finishing material.

Each roofing material has its own permissible range of roof slope angles

The angle of inclination of the roof slope determines the position of all rafters. The installation location of the intermediate rafters is calculated as follows:

A center line is drawn on the top beam of the side wall.
The middle of the ridge beam is determined by thickness and the location line of the first of the center intermediate rafters is marked.
The end of the measuring strip is connected to the location line of the previously marked center support rafter.
At the other end of the plank, the line for the location of the internal contour of the end wall is marked.
The point that will be obtained at the previous stage will be the installation location for the intermediate rafter.

The relationship between the size of the rafters and the length of their laying (horizontal projection) is determined using a correction factor, the value of which is directly proportional to the angle of inclination of the slope. If you multiply the size of the laying by this coefficient, you can determine the exact length of the rafters.

Table: correction factors for determining the length of rafters

Slope roof slope	Coefficient for intermediate rafter	Coefficient for corner rafter
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

Formulas for calculating rafter structures

In the process of developing a project for any roof, you should determine exact angle slope of the slope, which is necessary for all subsequent calculations.

Calculation of hip roof area

The roof area is calculated as follows:

We determine the height of the ridge using the formula h = d / 2 · tg α (where d is the width of the building, α is the angle of inclination of the slope, h is the height of the ridge).
We calculate the size of the side rafters using the formula c = d / 2 · cos α.
Find the length of the diagonal rafters l = √(h 2 + d 2 /4).
We calculate the area of the roof by adding up the areas of all structural elements (two trapezoids and two triangles):
- area of the triangular slope S 1 =1/2 · d/2 · c;
- area of the trapezoidal slope S 2 = 1/2 · (b + k) · e, where b is the length of the cornice, k is the length of the ridge girder, e is the height of the trapezoidal slope;
- S = 2 · (S 1 + S 2).

To determine the area of a hip roof, it is necessary to use formulas for the area of simple geometric shapes: triangles and trapezoids

Calculation of the distance between rafters

Most rafter systems are created with a pitch between two rafters of 1000 mm. The minimum acceptable pitch is 600 mm.

We select the approximate distance between the rafters, guided by standard sizes(for example, let's take this parameter equal to 0.8 m).
We measure or take the length of the slope from the design documentation. Let's say it is 12 m.
We divide the length of the slope by the previously selected value of the rafter pitch, round the total up and add 1. We get 12 / 0.8 + 1 = 16.
We divide the length of the slope by the number obtained in the third point. The final pitch of the rafters will be 12/16 = 0.75 m = 75 cm. The resulting value will be equal to the distance between the central axes of the rafter joists.

Preparatory work

The rafter system drawing is prerequisite when constructing this type of roof, since there are no identical schemes that are ready for immediate use without taking into account the specific type of building and the location of its construction.

The more complex the roofing system, the more accurate the calculations must be, since they will affect not only the quality of the work performed, but also their cost.

The drawing of the main components of the structure must accurately indicate the dimensions of all elements rafter system, the location of the junction points of the diagonal posts to the ridge beam and the attachment points of the rafters to the mauerlat.

Tools required to assemble the structure:

construction level;
hacksaw;
large hammer;
long tape measure;
construction cord;
stapler;
electric drill;
riveter;
metal cutting shears;
nails;
measuring bar.

Materials for work:

When installing a hip roof on a house made of timber that shrinks, experts recommend using special floating fasteners for the rafters to compensate for the movement of the crowns.

When installing a rafter system in wooden house It is recommended to use a sliding rafter fastening system, which compensates for the deformation of the building during its shrinkage

Video: ensuring the rigidity of a hip roof

Features of the hip roof rafter system

All types of hip roof truss systems have identical parts that create the frame of the structure:

Video: assembling rafters

Technology for creating a hip rafter system

Since a large load is placed on the roof truss structure, all components and connections must be made in strict accordance with the technology, otherwise the roof will not be able to fully perform its functions.

Installation of main components

Installation of units comes down to the following steps:

We prepare the rafters. We determine the angle of inclination of the rafters, the length of short supports and slanted rafters, which carry a significant load. In order to obtain all the elements of the required length, we use the method of overlapping boards. To do this, we lay two boards on top of each other with an overlap of 1 m and fasten them with nails arranged in a checkerboard pattern. This is the simplest and most durable way to splice rafter legs.
The most durable and reliable method splicing of rafter legs is an overlapping fastening
We fasten the Mauerlat. We install timber along the entire perimeter of the walls of the building in the upper part. We connect the timber with an overlap using large quantity attachment points with the base of load-bearing walls. The connection nodes are fastened with metal staples.
The Mauerlat beam is attached to the upper end of the wall using anchor bolts
We lay a layer of roofing material between the wall and the beam to create a water barrier. In brick, aerated concrete, foam concrete and wood concrete houses, a reinforced concrete belt with pre-fixed pins for installing the timber is poured under the Mauerlat. The pin must have a diameter of at least 10 mm and protrude approximately 30 mm beyond the belt. The pitch between the pins is from 1 to 2 m.
A layer of roofing material creates a water barrier between the Mauerlat and the wall made of moisture-absorbing material
We install a beam - a central beam between the two short sides of the mauerlat to provide additional strength under the rafters. Such a run is necessary to create a hip roof of a large area.
We install support posts. They act as supports for the ridge girder.
Support posts are mounted on the bed and serve as supports for the ridge girder
We install the ridge beam. When installing the ridge of a hip roof, precise measurements should be taken, since it will support the entire roofing system. We check the accuracy of its installation with a level in height.
Carrying out work on the installation of a ridge beam requires accurate measurements, since it carries the greatest load in a hip roof system
We nail the rafter legs. We install the central rafters, and after them the diagonal ones. During installation, we rest the lower part of the beams against the Mauerlat. This can be done in two ways: with a cutout or with support posts. In the first case, we cut a groove in the Mauerlat, insert the rafters into it and secure them with metal corners. In the second case, we simply place the rafter on the mauerlat and place a block with an oblique cut under it. We also secure them with a metal corner.
Rafter legs can be attached to the mauerlat in two ways: with a notch and on a support block
We install the unit on the ridge beam using the “half-tree” method. To do this, we cut out a notch at the end of the rafter legs, which should be equal to half the thickness of the board. Then we connect these recesses to each other and secure them with nails or dowels. The result is a strong ridge knot. For greater strength, all nodes are secured with steel corners.
To create a durable ridge assembly on a hip roof, the “half-tree” cutting method is used.
There is a lot of pressure on the diagonal rafters, so we strengthen them with the help of racks that we mount on the ceiling or install struts at a certain angle. You can use a sprengel in the form of a T-shaped beam rotated 180°.
The sprengel is one of the auxiliary elements to ensure the necessary rigidity of the rafter system, transferring part of its load to the power plate
We install ordinary rafters similarly to the central ones, forming the edges of a trapezoidal structure. We support the bottom of the beam and fasten it to the mauerlat, and rest the top against the ridge beam.
We install spigots, which we make from a solid board. In the place where they are attached to the long rafters, we make special notches or install support beams and provide the necessary strength with the help of metal fasteners. To simplify the work, the spigots can be installed staggered.
The flanges are attached using a notch into the rafter beam and are installed in a checkerboard pattern

Before assembly, all wooden parts of the rafter system are treated with special fire-resistant and antiseptic agents.

Video: hip roof rafter system

Creating a hip truss structure is a long and complex process that requires attention to every specific detail. But if you carry out all stages of work correctly and accurately, the result will be a beautiful, durable and reliable roof for your home.

Supporters of the European style in the construction of country real estate in most cases opt for a hip roof, the advantage of which is not only visual appeal, but also the reliability of the structure. By choosing even the simplest option, you can use a lot of interesting elements that can give the structure a special sophistication and uniqueness.

What is a hip roof

The simplest hip roof is made in the form of a frame with four slopes: two triangular end slopes, called hips, and two front trapezoidal planes. All slopes are laid from the ridge element to the cornice, with the front surface having a larger area and length of the slope.

In addition to the standard design, there are half-hip roofs, which are usually used to create a Dutch-style design. This option involves installing the cornices of the front slopes significantly lower than the end ones. It is advisable to erect such a roof when arranging an attic space as a living space.

All four slopes of the hip roof converge on a ridge beam, which is smaller in size than on gable roofs

Installation of a hip roof is carried out on the basis of the assembly of components and elements that are also present in structures of more complex roofs.

The main frame of the structure is assembled from the following elements:

For the manufacture of side rafters and intermediate systems, boards with a cross section of 50×150 mm are prepared. When constructing the structure, it should be remembered that the outer rafters should have a smaller angle at the top than the intermediate ones.
The installation of short rafter legs is carried out to the corner rafter, and not to the ridge, and their angle of inclination should be the same as that of the intermediate parts.
For ridge elements, select material of the same cross-section as for the rafters.

In the frame of a hip roof, it is customary to distinguish central and intermediate rafters. Central elements are those that are joined at the corners of the ridge beam with three sides. Intermediate rafters are located between the central ones and connect the ridge to the mauerlat, forming a cornice.

The central rafters converge on the ridge element on three sides

Additional, but no less important when building a hip roof are the following factors:

Photo gallery: houses with hip roofs

All hip roof vaults square house converge at one point. Part of the structure can be brought out onto the slope of the hip roof attic space The house may have extensions covered with a similar roof. The roofs of several equal parts of the house can be combined into single design The slopes of a hip roof can be made of glass. A hip roof looks great on medieval-style buildings

Self-construction of a hip roof: detailed instructions

Do-it-yourself roof installation requires strict adherence to the construction stages, as well as the availability of skills similar works and a set of special tools.

List of tools and materials for the construction of a hip roof

Installation of a roof frame is impossible not only without quality lumber or roofing, but also without the corresponding fastening elements.

Metal fasteners include:

nails and screws for roofing work;
anchor bolts;
steel corners;
other details responsible for the reliability and strength of the structure being built.

An important point in the arrangement roof frame is the installation of sliding fastening of trusses both at the ridge and at the junction with the Mauerlat. This method of fixing rafter elements eliminates the possibility of damage roofing system due to shrinkage of load-bearing walls and seasonal deformations of the building .

Sliding fastening allows rafter elements to move within permissible deviations with small deformations of the building frame

The rafter structure is assembled from the following materials:

The Mauerlat is made of timber with a section of 100×150 mm.
For the ridge and rafters, a beam with a cross section of 50×150 mm is selected. Experts involved in the installation of rafters recommend using timber or boards with the same cross-section; only then will maximum strength and quality of the structure be achieved.
The rafter system is equipped as soon as it is ready wooden sheathing with a board section of 25×150 mm.

When choosing a roofing material, several options are offered, among which the best is considered soft roof. It is easiest to attach to complex rafter systems like hip . Before installing the covering, a layer of insulation and vapor barrier film should be laid; if necessary, additional plywood can be attached.

Before you begin installation roofing pie, all wooden parts of the rafters should be treated with an antiseptic.

Installation of the structure will be carried out much faster if you have at hand necessary tools:

Video: how to cut rafters in a hip roof

What you need to know when designing and drawing up construction estimates

The roof design can be anything depending on the needs and capabilities of the owner of the house. The complexity of the work will depend on the location of the load-bearing walls. As the project becomes more complex, the consumption of materials, labor costs, and order execution times increases for its implementation.

The complexity of erecting a hip roof primarily depends on the size and configuration of the building

It is better to leave the construction of a complex hip roof to professionals who will perform accurate calculations of all elements of the rafter system and will be able to produce the roof in strict accordance with the project. For those who like to try their hand at self-construction Several factors need to be taken into account:

The ability of the structure and foundation to withstand the load of the future roof.
Features of the rafter system - layered and hanging structures have their own subtleties of implementation.
Allowable section size wooden elements structures for given lengths and distances between trusses.
Correspondence of slope angles and rafter purlin when bringing them together on a skate.
The need to organize additional openings and projections, for example, for chimneys, ventilation, windows and other openings.

When designing a rafter system for a hip roof, many different factors must be taken into account

Step-by-step instructions for installing the rafter system

First, the wood is prepared - it is well dried, treated with antiseptic compounds and dried again. Once the material is ready, you can begin its installation according to the scheme below:

Along the perimeter load-bearing base the mauerlat is laid and securely fastened with a mandatory waterproofing layer made of roofing felt or similar materials.

The roof Mauerlat is laid on the waterproofing material and secured with studs
The Mauerlat is marked according to the previously calculated dimensions. To make the marks clearly visible, it is recommended to apply them with a bright marker or even drive in small beacons. It is important to maintain identical markings on opposite planes, otherwise the laying of the beams will be uneven.

The markings must be done very carefully so that roof trusses and the puffs were installed evenly
Installation of floor beams is carried out on a mauerlat or on an additional beam reinforced just below the plane of the walls.

Floor beams (tightenings) can be mounted on the Mauerlat
To reduce the load on the supporting frame, the Mauerlat is fastened using transverse ties.

Transverse ties redistribute the load from the roof evenly along the entire perimeter of the rafter system
After completing the laying of the ties on top of the floor beams, it is recommended to build a boardwalk for fastening to the beams. It will be convenient and safe to walk on it when performing further work.

Temporary flooring is used for safe movement across the entire area of the floors when installing rafters
Next, racks are installed to the tie rods or to the floor beams.
At the top, the posts are attached to the ridge beam. The central rafters from the end of the roof are also mounted on it.
Then the marking and installation of intermediate rafters on the side of the gables is carried out.

Intermediate rafters are installed from the front side
After this, diagonal rafters are laid, connecting the ridge element of the building with the corners. If necessary, it is possible to install additional racks.

Diagonal rafters connect the roof ridge to the corners
Short rafters called sprigs are fixed to the diagonal rafters. The distance between them should be the same as between the intermediate elements.

Narodniks connect diagonal rafters to the Mauerlat
The design diagram may also include other support and reinforcement parts: struts, wind beams, truss system.
If the rafters end on the surface of the mauerlat, they must be extended beyond the building frame using “fillies”, due to which cornices and roof overhangs are created.

Rafter legs can be attached to the Mauerlat using various rigid elements, for example:

The rafter legs are also attached to the beam of the ridge element in several ways:

Connecting the legs above each other and above the beam, followed by bolting.
Creating recesses on the rafters to enhance the rigidity of the connection with the ridge element.
Bringing the rafters to the ridge and then fastening them together using wooden or metal plates.

At the point where the ridge beam is attached to the rafter legs, a rather complex knot is also obtained, and only with reliable mating and fixation of all parts can we talk about the durability of the hip roof. In this case, the ridge beam is laid on top of the posts, after which it is fastened with wooden plates on both sides. Then diagonal rafter elements are cut out, which are attached to the ridge and intermediate rafters. The installation of the second rafter for the other corner of the house is carried out in a similar way.

Video: DIY installation of a hip roof rafter system

Preparing the roof for laying roofing

When the rafter system is completely installed, you can begin preparing the structure for laying the roofing material:

Marking is carried out in the places of planned window and doorways, exits of chimney pipes, ventilation openings with subsequent framing of selected openings wooden slats.
Next, the roofing pie is installed in the following sequence:
1. A layer of vapor barrier film is stretched and attached to the rafters.
2. The next layer is the sheathing.
3. Insulation with wind protection according to the type is attached to the spaces between the slats polyethylene film.
4. Next, the counter-lattice is installed.

The last stage before installation of the covering is directly determined by the selected roofing material. So, if the choice fell on metal tiles, then it can be attached directly to the counter-lattice. If a soft roof is used, then an additional layer of plywood or OSB sheets will be needed.

It is recommended to strictly follow the rules for laying roofing material

Installation of a roof ventilation system

For air intake from the under-roof space vent is done at the bottom of the wind sheathing, and to bring it out - in the upper part of the roof - closer to the ridge element. When creating a binder from wooden boards you can leave a small gap between them, which will create better ventilation.

When assembling the filing tightly, it is recommended to make several small wooden grids and lay them out along the entire length of the wind filing in increments of 80 cm. To drill the required hole, you will have to arm yourself with a drill with a cup attachment. The place for the upper air outlet is equipped in the roof itself.

When using flexible tiles ventilation is carried out by means of a ventilated ridge, ceramic tiles allows air supply through a roof vent. Ventilation of slate, ondulin and other similar coatings is carried out through standard skates. The metal tiles are ventilated using a ridge seal.

Video: hip roof made of metal tiles

Gazebo with hipped roof

A gazebo with a hip roof will become a standard design solution, and subject to proper calculation and arrangement, it will be distinguished by its reliability and durability. It will not be difficult to assemble a hipped roof yourself. This design is suitable for a gazebo in the form of a rectangle or square. The first option is an assembly of a hip structure with two triangular and the same number of trapezoidal slopes. The second option is a hipped hip roof, consisting of 4 isosceles triangular slopes.

Hip roof for square gazebo consists of four identical triangular sections

A hipped roof is an excellent choice when building a gazebo, since it allows the use of any roofing covering, and its convenient design provides a free viewing angle; it can easily be arranged, for example, in chinese style, adding length to the overhangs and several curved diagonal rafters.

On preparatory stage work, a drawing of the future roof is made, taking into account the main factors:

the weight of all rafters and their additional elements;
roofing and waterproofing masses;
level of climatic loads, layer of snow masses;
the weight of the builders servicing the roof;
loads from equipment that is planned to be installed on the rafter system.

The installation features, for example, the spacing of the sheathing slats and rafter system, directly depend on what the slope of the slopes will be and what materials are chosen for covering the roof. And all this affects the overall weight of the building.

You can extend the service life of a wooden gazebo by pre-treating all its elements with special antiseptic impregnations, as well as a fire retardant. All these compounds can be applied quite simply with a regular brush or roller.

The support for the hipped roof of the gazebo can be wooden, brick walls or racks of the supporting frame. If brick is used in the work, the structure will be capital and will require the construction of a solid foundation capable of withstanding heavy loads. The construction of a hip roof on such a gazebo is generally similar to the installation of a roof on a residential building or other large structure.

Small hip roofs can be assembled on supports made of pillars, which must first be well secured

If the gazebo is installed on wooden poles, then you should first check the strength of fastening of its supports; they must stand strictly vertically, and for the rigidity and stability of the frame they are tied with jumpers from below. Jumpers are also mounted on top, which will serve as strapping for the pitched structure. Due to the high load, the supports can gradually move apart, so it is recommended to fasten them at the upper ends in advance using diagonal jumpers, and lay wooden or steel pads at the joining points.

Step-by-step instructions for installing a hip roof for a gazebo

A hip roof is assembled in the same way as a regular hip roof, excluding the installation of a ridge beam. In this case, a bunch of diagonal rafters are connected into a ridge unit.

Video: building a gazebo and barbecue with your own hands

Lack of construction experience roofing structures may have a negative impact on quality future roof and the degree of protection of the entire structure, therefore, to perform this type of work, it is recommended to turn to professional construction teams. At the right approach a hip roof will be an excellent architectural design for a house, gazebo and any other buildings.

(hatched, hipped) roof is one of the design options when additional slopes are built in place of the gables.

Nevertheless, hip designs are widespread, especially in areas with frequent changes in wind direction.

The result is a roof with inclined planes on all sides, which creates a lot of advantageous positions:

The absence of gables makes the load on the foundation less, and it is distributed absolutely evenly.
The wind load on the slope is much lower than on the vertical plane.
The costs of finishing the gables are excluded from the total repair estimate.
Decoratively, the hip roof looks more solid and assembled.

The disadvantage of this design is:

Increased complexity of the rafter system design.
Higher flow rate, which creates additional dangerous areas of possible leaks.
The presence of bursting loads on load-bearing walls, necessitating the need to tie down the lower bases of the slopes.

The main design feature of a tent-type rafter system is the presence of diagonal edges, connecting the corner points of the roof with the ridge beam, which has a shorter length than the entire roof (the classic hip roof does not have a ridge at all, the ribs converge at one point).

In the rafter system, these ribs are called corner or diagonal. Their presence requires installation as full rafters, going from to the base - the Mauerlat, and shortened elements- splices connecting the base and diagonal rafters.

Hip roof scheme

Hip roof: elements of the rafter system

The elements of a hip-type rafter system have a more numerous composition than with gable design. The rafter system consists of the following parts:

Mauerlat. A beam laid along the perimeter of load-bearing walls and serving as the basis for the entire rafter system.
Sill. A horizontal beam of the same cross-section as the Mauerlat, located along the longitudinal axis of the roof and serving as a support for the purlin posts. A layer is required between the ceiling and the floor.
Sprengel. Element that binds and strengthens corner connections Mauerlat bars. It is made from the same timber as the Mauerlat and is installed diagonally to it.
Puff. Connecting elements connecting the parallel bars of the mauerlat along the long side. Remove the bursting load from load-bearing walls.
Rack. A vertical element supported by a tie and supporting a ridge beam.
Run. Ridge beam.
Diagonal (corner, slant) rafters. Connects the corners of the Mauerlat with the ends of the purlin, forming ribs - the junction of the roof planes.
Rafters. Inclined elements resting on the mauerlat from below and on the purlin from above.
Narozhniki. These are the elements that rest on top of the diagonal ribs. Essentially these are rafters cut to the length required at a given point.
Struts. Reinforcing elements, spacers located perpendicular to the rafters and resting at an angle on the tie rods.

The designs of all elements may have deviations from the generally accepted design due to the necessity caused by the design features of a given building, but the scheme as a whole almost always consists of the named parts and does not have any radical changes.

Hip roof rafter system: diagram and photo below.

Rafter system diagram

Photo of the rafter system

Diagonal rafter legs

The elements of the rafter system that form the ribs connecting the planes of the slopes are called diagonal (oblique, corner) rafter legs.

Strictly speaking, diagonal and oblique - not entirely identical elements, since the former are attached to the outside of the corners of the Mauerlat, and the latter - from the inside.

Otherwise, all properties are the same.

Corner elements have certain features:

The length of the diagonal rafter legs significantly exceeds the length of the straight rafters.
Diagonal rafter legs serve as support for the frames on both sides of the connecting planes.

The presence of such features creates an increased—about one and a half times—load on slanted rafters compared to conventional ones. Their length exceeds the usual length of the boards, from which the rafters are made, therefore, to make the slope boards, they are welded together - they are connected along the plane in two layers.

This solves several problems at once:

You can make beams of any desired length.
Ability to use one modular material size.

One or two supports must be installed under the diagonal rafter(depending on the length), and the point of support is not in the middle, as it would seem at first glance, but at a distance of one third to a quarter of the entire length of the slanted rafter, counting from the top point, since it is in this area that the place of greatest stress is located.

Diagonal rafter legs

Supports for diagonal rafters

Either struts or vertical racks from timber or paired boards. The stand can rest directly on the ceiling, through a layer of waterproofing and a wooden lining.

This requires sufficient rigidity and strength of the floor. If such conditions do not exist, then a strut is used, resting on the beam and supporting the slanted rafter at a given point.

The angle of inclination of the strut does not play a role in this case., the main thing is the connection point, i.e. Load concentration location. For a rafter length of up to 7.5 m, a brace from the top point of maximum load is sufficient, but for a length of more than 9 m, an additional support is required at the bottom.

This can be either support on the ceiling, if it allows, or support on the truss - the so-called. truss truss - a stand reinforced with struts on the sides.

Supports for diagonal rafters

The device of the narozhniki

In the lower part there are rafters - the same rafters, have a completely similar method of attachment to the Mauerlat, same installation step. Mounted strictly at right angles to the base, the upper part - to the corner rafter leg.

Fastening is carried out with at least two nails or other elements. Upper part Narozhnik gets cut under the right angle to the horizon and to the diagonal rafters, to ensure a tighter connection and guarantee resistance to loads.

The device of the narozhniki

Hip roof over bay window

A bay window is a solid-looking structure that decorates a building, which represents small extension, a protrusion in the wall that performs mainly decorative functions. The section of the roof above the bay window can be of any type of structure, but most often the option that is most suitable for the shape and cross-section of the bay window is used.

The hip roof above the bay window may have an adjacent form, i.e. be half of a hip roof, a complex of three planes. Alternatively, there may be a dominant dome over the bay window, rising above the main roof.

Anyway, erection of such a structure - difficult task , and the complexity is not in the technical sense, but in design and calculation work. The combination of several planes into one ensemble is a complex problem that requires precise and careful thoughtful work.

ATTENTION!

Lack of experience combined with haste can cause inconsistencies or miscalculations, leading to violations of the roof's tightness and a decrease in the strength of the structure.

Available important points, playing a significant role - for example, the angle of inclination of the bay window slopes must correspond to the angle of inclination of the main roof, the length of the fillies must also be in harmony with all the roof overhangs.

The main feature is the combination hip elements with the valleys, therefore the construction of the main rafter system should be carried out parallel to or up to the bay window to avoid unwanted discrepancies in the system geometry.

Hip roof over bay window

Step-by-step instructions for installing a hip rafter system

The description will begin from the moment the mauerlat is laid, all previous operations are considered completed, the ceiling is completely ready.

All calculation and design work has also been completed.

There is prepared (dried) material - timber and edged board from coniferous trees, as the most suitable for the construction of a rafter system in all respects.

For correct installation elements of the rafter system, it is necessary to stock up on connecting elements, allowing some movement of parts relative to each other.

This is necessary to compensate for the shrinkage processes of the walls, foundation and the system itself. This is especially important for some load-bearing elements, resting on the mauerlat.

Movements of the base with fixed connections of the main components can lead to weakening of the connections and the formation of leaks.

Let's consider the stages of constructing a hip rafter system:

Mauerlat installation. The timber is laid on a waterproofed base and secured with studs. If necessary, the segments are connected along the length of the “half-tree”, with the connections reinforced with nails. The fasteners are installed immediately.
The corners of the Mauerlat are reinforced with trusses And.
Installation of the bed. One or two (depending on the project) planks are laid on a waterproofed base.
Racks are being installed, on which the purlin is attached. In this way, the supporting skeleton of the rafter system is created.
Diagonal rafter legs are being installed. Immediately, depending on the length, struts and (or) racks are installed.
Rafters are installed according to design data. The length/angle is immediately adjusted and the spigots are installed. All elements are, if necessary, reinforced with struts.
The rafters at the points of attachment to the base and to the purlin are additionally reinforced with brackets, wooden blocks and other fasteners.

Actually, the installation of the rafter system is completed at this stage. Further work consist in creating a roofing pie, constructing sheathing, laying the roof, etc.

It is necessary to take into account the impossibility of complete and detailed coverage of all the nuances and details, on which the high-quality and reliable construction of the rafter system depends, since there are many of them and they are all worthy of separate consideration. Nevertheless, the general sequence is reflected in sufficient detail.

Creating a hip rafter system is not so much a complex process as it is responsible and dangerous because mistakes made on early stages, become noticeable much later.

That's why it is very important to draw up before starting work detailed plan works, ensure full compliance with the project and do everything as carefully as possible. Everything depends on connections wooden parts Therefore, it is advisable to have experience and skills in working with wood.

Without possessing this knowledge, it is better to seek help from specialists, since the responsibility of the rafter system for preserving the functional qualities of the entire building is too great.

Hip roof: drawing of the rafter system below.

Drawing of the rafter system

Useful video

In this video you will learn everything about the hip roof rafter system:

This roofing option has four slopes. Its two long inclined surfaces have a trapezoidal shape, and the other two, smaller ones, have the shape of a triangle - they are called hips. They are located along the gables of the building and connect the ridge to the cornice. Trapezoidal planes have large area and a slope, also located from the upper horizontal edge to the cornice.

The hip roof has several different designs:

Traditional with two trapezoidal slopes and two hips, it is called a “Dutch” roof.
Tent - has triangular-shaped slopes of the same size. Ideal for square-shaped buildings.
Half-hip - the hips cover only the upper part of the end no more than to the middle. Suitable for the construction of houses with an attic; it is called “Scandinavian” roofing.
Semi-hip - the hips are not triangular in shape, but are in the shape of small trapezoids. Such a roof gives great attic room, it is also called “Danish” roofing.

Like any other type, the hip roof type has a frame and rafter system - the entire structure rests on them.

Construction of the rafter system

The rafter system is the main component of the entire roof structure.

Unlike a gable roof, the structure of the supporting structure of a hip roof is more complex.

Regardless of whether the building is rectangular or square, the shape of the slopes will not change.

Considering the structure of the hip roof rafter system, we can determine that it consists of several elements:

Mauerlat is the base for the rafters, the connecting link between the load-bearing walls and the rafter system.
Oblique or diagonal supports - have the greatest length and carry the greatest load.
Central rafters - serve to connect the ridge with the mauerlat on the sides of the slopes, converge at the corners of the ridge on 3 sides.
Intermediate rafters - connect the ridge and cornice.
Struts - create not only rigidity, but also provide confrontation to wind loads from the gables of the building, located at different angles to the rafters.
Narozhniki are the shortest rafters.
Sprengels or truss trusses - enhance the load-bearing capacity of the roof structure. They are a beam made of timber located at the corner of connecting external walls.
Racks - give the legs of the supports additional stability; they are installed at the junction of two rafters and a ridge beam.
Corner rafter (rib) - located at a smaller angle than the intermediate elements of the system.
Short rafter legs - fixed to a corner support board.
Horse.
Tightening - performs the function of a floor beam.
Wind beam - attached with a slope on the windy side of the roof.
Purlins - the distance between the connection of supports to the ridge.

Installation of rafters

After the type of roof has been determined, all necessary building materials, you can directly proceed to the construction of the frame.

Before starting the construction of a supporting structure, it is necessary to draw up its design and drawing.

So, the design of the support system consists of several stages:

Before starting construction, a wooden beam should be laid around the perimeter of the outer wall - a mauerlat. To install it, you need to equip reinforced belt made of reinforced concrete structure, reinforcing load-bearing capacity walls You should pay attention to ensure that the Mauerlat is securely fastened, preventing the slightest movement.
If the walls are made of stone or brick, formwork is erected on top of them, into which a reinforced frame is mounted using galvanized threaded rods with a caliber of at least 10 mm. The upper part of the studs should protrude 4-5 cm from the base for the supports (mauerlat).
After installing the frame, fill it with cement mortar.
Then, as the concrete hardens, its surface is covered with bitumen and covered with a layer of roofing material or other waterproofing materials.
Beams with drilled holes are placed on the protruding part of the studs. Secure the structure with nuts.
The Mauerlat is made from 10*15 or 15*15 cm pine needles, dried and impregnated with anti-corrosion and fire-retardant agents. The humidity of the wood should not exceed 20%.
The next step is to install the central beam on the mauerlat, which is located parallel to the ridge. Stands are attached to it. These posts serve as support for a specific part of the support system.

When starting work, you need to check and double-check everything step by step. This is the only way to protect yourself from mistakes and ultimately achieve the most durable structure possible.

Types of hip roof rafters

Hip roof supports are divided into two types:

Hanging - beams are located on a beam ceiling two external walls without additional support.
Layered – along the top edge interior walls there is a horizontal beam to which they are attached vertical supports. The basis for the end part of the beam is the external walls.

The layered type of supports is suitable for buildings with an intermediate supporting wall or columns.

This supporting structure has more base points, so it can be made much easier.

If the building has two load-bearing walls, a screed is installed to support the rafter legs and distribute the load across all vertical supports.

For a hip roof type, a layered system is considered the most suitable, giving greater strength and facilitating the roof structure.

This modification is used when constructing an attic or mansard roof.

How to calculate the rafter system of a hip roof

Calculation of the supporting structure is the main stage of roof design. The slightest miscalculation can cause deformation or destruction of the roof.

After studying the roof structure, it is necessary to calculate the angle of inclination of the rafter system. The higher it is, the more the roof is exposed to winds, but it clears itself of snow and ice on its own.

The angle of inclination of the slopes can be 5-60 degrees, it depends on the load of wind and snow.

After determining the angle of inclination, calculations should begin to determine the main loads to which the roof is exposed. These include the weight of the roof itself and natural phenomena - wind and precipitation.

The total weight of the supporting structure, sheathing, covering and insulation is divided by the area of all inclined planes. The resulting value shows the load per 1 m2 of roofing. For a residential building, it must withstand a load of 45-50 kg/m2. This figure is the same for any area.

Sediment loads vary depending on the area and range from 80-150 kg/m2. This value can be found using the “Building Codes and Regulations”.

The load value must be multiplied by the correction factor:

At 1.0, when the angle of inclination does not exceed 25 degrees;
By 0.7 if the angle is 25-60 degrees.

If the roof is subject to regular heavy snowfalls, it is recommended to install double supports or continuous sheathing.

Determining the wind load involves using the wind pressure coefficient.

The load indicator (wind and snow) is multiplied by an index equal to the rafter pitch value. The pitch of the rafters is determined in meters.

The final stage is the calculation of the quantity and criteria of materials.

After calculating all the loads per 1 m2 and the area of the entire roof, determine the cross-section of the supports (smallest values):

Mauerlat – 10*10 cm.
Tightenings and purlins – 5*15 cm.
Fillers, struts, crossbars – 10*10, 15*15 cm.

The number of beams on which the sheathing and additional elements are attached is calculated by the length of the roof. For example, the length of the roof is 12 m, the pitch between the rafters is 1 m. Based on this, you will need 24 construction legs, 12 on each side.

When carrying out calculations for large-scale projects, it is recommended to use special computer programs for design.

All obtained indicators must be plotted on the drawing.

Nodes

Precisely calculated nodes make it possible to achieve strength and attractive appearance roofs.

The connection of roof structural elements is carried out in accordance with certain requirements.

Main components of the supporting structure:

ridge unit - a pair of supports are fastened with nails or bolts, and reinforced with bolted beams;
the support unit for the beams on the Mauerlat is reinforced with metal corners, construction staples, nails or bolts;
rafter connection unit with a tightening, which is located in the middle of the rafter - carried out using nails or bolts;
the combination of the strut, rack and support is done using a die cut and reinforced with construction staples.

Rafter system

The quality of the roof directly depends on the frame and base for the roof deck. Load-bearing structure The roof serves as the basis and determines its service life.

Rafter system for mansard hip roof

This support system is resistant to strong wind loads due to the absence of a roof façade wall.

A roof of this form makes it possible to build large plumbs that protect the walls and foundation of the house from rain, snow and ice.

Components of the attic roof rafter system:

Mauerlat.
Ridge and side girders.
Support beams.
Layered and hanging rafters.
Struts.
Support posts.
Diagonal rafters.

A distinctive feature of the mansard hip roof is the use of layered and hanging rafters in its design. The upper slope is made from hanging rafters supported on racks or a side girder.

To avoid bending, they are equipped with drawstrings. When installing the lower slope, layered rafters with a base on the Mauerlat are used, and a horizontal beam connecting the rafter system in its middle part.

The lower sloping surfaces have an inclination angle of about 60 degrees, and the upper ones - at least 30 degrees.

Strengthening the rafter system

To ensure the strength and durability of a hip roof, it is not enough to manufacture a rafter system; it must also be strengthened.

The most common methods of strengthening are:

Installation of trusses at the corners of the roof with a stand supporting the diagonal support. If the truss is located far from the corner, it is best to attach a truss truss to it.
Installation of racks connected from above by a beam on the ceiling (reinforced concrete) or tightening. They act as supports and ensure even distribution of the load on the house.
The use of double beams instead of one beam if the diagonal rafters are too long.
Using wooden boards 40*40 or 50*50 mm to construct the sheathing.

The hip roof rafter system is a type of hip roof.

General scheme The hip roof rafter system consists of four slopes, two of them have the shape of a triangle, the remaining two are made in the form of trapezoids.

In this case, the trapezoidal shapes are connected to each other by straight upper edges, and the resulting side openings are equipped with triangular slopes.

The advantages of using a hip hip roof are its aesthetic appearance and saving on consumables.

In addition, the hip roof rafter system is great solution for home improvement attic floors and a bay window.

But unlike the construction of other types of roof systems, the construction of a hip roof rafter system requires much more labor.

Types of rafters and main components of a hip roof

To design a hip roof structure, a diagonal or intermediate rafter arrangement can be used.

Also, the elements of the hip rafter system are divided according to the technology of the device into layered and hanging.

The first type of rafter structure is considered an economical and proven option. Most often, such systems are used for buildings with a frame support type or with a load-bearing central wall.

The second rafter system is difficult to install; it is usually installed on external wall openings.

Hanging rafters are attached only to the mauerlats and to ridge run, they are used if the distance of opposite walls does not exceed 6.5 m.

The rafter parts are made from dry timber 150x50 mm, pre-treated with an antiseptic.

Here is a photo of the design of the hip roof rafter system.

The rafter diagram for a hip roof contains:

slopes (placed diagonally or directed to the corners of the walls);
trapezoid elements;
short bars - trusses;
slopes, support posts.

The bevel parts are attached diagonally: one side to lower support structure or to the beam extending it, and the second side is fixed to another pair of rafter elements.

Unlike conventional systems, these roof rafter parts, given their size, are much larger.

They can take on more weight and act as a support for external rafter parts that do not reach the ridge beam.

The main parts of the hip roof system are: load-bearing beams and a skate. In turn, beams are divided into two types.

The first type of beam is made from the material used for rafters. It is located transversely and serves as a support for the posts supporting the ridge span.

Mauerlat is the second type of beam; 100x150 mm beams are used for its production. The beam is placed around the perimeter of the object.

If the building is made of wood, the upper crown will act as a mauerlat.

Calculation of rafters for a hip roof

When designing a hip roof yourself, you need to pay attention to the choice of material, as well as take into account the amount of precipitation and wind strength.

Oddly enough, but based on these facts, it is possible to correctly calculate the slope and height of the roof.

The slope angle of trapezoidal slopes can be from 50 to 60°; an example can be seen in the photo. Which figure is optimal will depend on the strength of the wind and snow load.

In case of heavy snowfalls, the angle of the slope is made large; in case of strong wind loads, the angle is made small.

Here it is necessary to clarify that the design of hip roofs becomes more complicated as the slope angle increases, and material consumption increases.

Having found out the height readings and slope angle, we will calculate the rafters using the example of a hipped roof design with two identical shapes trapezoids and triangles.

The calculation may have the following order:

When the slope angle is noted as the main indicator, then the height of the ridge beam is calculated as follows: (tangent of the angle) x (by the step size between the edges of the slopes) / 2. Based on the roof height indicator, the calculation is made in the opposite direction. Determine the tangent of the angle: (roof height) x 2 / (for the gap between the edges of the slopes);
The length of the roof slope is calculated using the so-called Pythagoras. The sum of the legs of the triangle is determined and the square is calculated. Using the same principle, the dimensions of the slopes are calculated by dividing the trapezoidal roof slope into two triangles and one rectangle.

Having determined the values and drawn up a drawing, a general calculation of the roof area is carried out. Total area calculated by determining the areas of the hip and trapezoidal sides of the roof.

The area of a trapezoid is equal to the sum of the values of its bases divided by two and multiplied by the height.

The area of a triangle is calculated as half the product of the length of the base and the height divided by two.

The roof area can be found by combining the values and multiplying them by 2.

Having made such a calculation, you can determine the quantity building material for the construction of a sheathing frame and a hip roof.

Also, using this value indicator, it is possible to calculate the required quantity of hydro- and heat-insulating products and the number of fasteners.

Hip roof rafter installation

The construction of the rafter system begins with the installation of beams. First of all, the installation of the Mauerlat is carried out, then the transverse beam.

The ridge support posts of the rafter system are mounted vertically and fixed with self-tapping screws; to strengthen the support posts, jibs are used. The skate should be exactly in the center of the object.

The material for the ridge and rafters is the same, with parameters of 150x50 mm.

Next, four sloping elements of equal length are mounted; special attention is paid to the work process, since it is at this stage that all the planes of the slopes of the structure are laid, which must have ideal evenness.

Diagonal rafters have the longest length, which is why you have to connect several rafter boards into one.

Each of them should be attached to the ridge beam and protrude 0.5 or 1 m beyond the wall of the house.

Thus, a cornice is installed as in the photo, which subsequently protects the walls from precipitation.

As for the cross-section of the rafter material, it is selected depending on the slope of the roof, taking into account the loads of the space between the main walls and between the rafters.

Installation instructions for intermediate rafters

When arranging a rafter system for a hip roof, the following instructions must be followed:

The intermediate and central rafters are attached to the top of the ridge beam, their second edge should protrude beyond the load-bearing walls. The required number of parts is determined taking into account the length of the house;
When corner elements are mounted, their upper edge is arranged on slopes. As they approach the corners of the walls, their length decreases.

A correctly drawn up drawing of the future structure, where the fastening points of the central parts are precisely marked, will allow you to eliminate the occurrence of inaccuracies when arranging the rafter system of a hip roof.

The classic method involves the initial installation of central rafters - 3 parts on each side. The fastening points are located along the edges of the ridge beam.

In order to install the first rafter on the hip, mark one point in the center of the wall on the mauerlat and the center point of the thickness of the ridge beam.

Then the central part for the trapezoidal slopes is installed, and all the intermediate rafters are installed parallel to them.

Double bevel cuts are made on central and diagonal elements that will intersect during installation. It is recommended to strengthen the connections with ties.

Features of installation of spigots

Corner rafters are mounted parallel to the main ones. A cut is made on the shortened parts, then each of them is laid and secured on slopes.

Fixation is carried out using self-tapping screws or nails. They can also be connected using a timber support fixed to a diagonal element or by cutting.

It is not recommended to connect the corner elements (springs) of a hip roof, triangular and trapezoidal slopes, in one place, with diagonal elements.

If the area of the house is large, then it is necessary to carry out a calculation, noting the degree of sagging of the intermediate and diagonal rafters.

The central element of the hip structure system is attached to the ridge beam using two wooden ridges.

In order to make the corners of the hip rafter system more durable, trusses (additional beams) are installed.

Their use makes it possible to support the diagonal elements of the rafters and thereby impart strength to the structure.

Lathing and insulation for a hip roof

The frame of the sheathing of the hip roof truss system is carried out in accordance with the instructions for the installation of the selected roofing material.

Installation of the sheathing can be carried out using wooden beams or boards. The cross-section of the beams should be 50x50 mm, the thickness of the boards should be at least 20 cm.

Sheathing structures can be continuous or with gaps; the spacing of their location will depend on the type and size of the roofing product.

When insulating a hip roof, three methods can be used:

thermal insulation material is mounted between the beams of the rafter system;
the insulation is laid directly on the rafters;
the insulating layer is placed under the rafters.

At the moment, the most common technology is the first option. Can be used as thermal insulation mineral wool, liquid foam or polyurethane foam.

When insulating a hip roof, it is important not to block the ventilation gap.

Depending on the chosen type of roof structure, a waterproofing material is selected, which is mounted on the insulating layer or under it on the rafters.