Sloped roof construction scheme. Do-it-yourself gable sloping roof. Sheathing, roofing works

Using the attic instead of a full-fledged second floor allows you to rationally use the available space and significantly expand the living space. There are many options for attics; the most popular of them is a sloping roof, which is not only aesthetically attractive, but also financially beneficial. If you wish, you can build such an attic with your own hands.

What parts does a broken attic consist of?

The first stage of roof construction is design and calculation; regardless of whether the project is ordered in a special organization or it is planned to make a design drawing on your own, first of all you need to figure out what main parts the broken attic consists of.

In essence, a sloping roof is a residential attic, well enough insulated and protected from moisture and noise to make it comfortable to live in. Therefore, in terms of design, it differs slightly from an ordinary gable roof.

vertical racks;
puffs - horizontal beams;
rafters - stiffeners, which are the skeleton of the entire structure;
struts - diagonal beams supporting the rafters;
mauerlat - wooden beams with special fasteners connecting the structure to the walls of the house;
ridge run - set upper elements truss system;
grandmas - fasteners that ensure the rigidity of the hanging rafters;
contractions - horizontal struts that remove part of the load from the rafters;
crate - a frame for fastening roofing material and insulation;
roofing - can be made of ceramic tiles, different types of slate, profiled sheet and many other materials;
heat, hydro and sound insulation.

Thus, the whole construction consists of a set of right triangles; they are connected to each other with wooden beams. All the elements described are easy to find on the drawing of a broken attic.

Technical requirements for sloping roof

Sloped roofs are subject to the following requirements:

the height of the attic walls must exceed 2.2 m;
should be provided good ventilation so that moisture does not condense under the roof;
roofing material should have a small mass;
the design must provide for measures against the impact of additional load on the truss system - that is, the roof elements must withstand not only their own weight, but also, for example, snow;
the attic loses heat faster than the lower floors, so special attention should be paid to thermal insulation;
to provide fire safety all wooden beams and batten elements should be treated with flame retardants.

Varieties of truss systems

The device of a sloping roof is very simple - its slope, as it were, breaks into lower and upper parts, each of which is set at its own angle. Most often they are mounted at an angle of 60–70 °, and 15–30 °, respectively.

Based design features attic can be distinguished such types of mansard sloping roofs.

Two types of rafters are used: hanging and layered. The attic floor beams are installed, a little short of the edges of the walls of the lower floor. The lower slope is made of layered rafters, which are attached to the walls of the house with the help of a Mauerlat. The frame of the attic walls is made from the racks. Such triangles are installed along the walls and connected by contractions. From above, they are joined by triangles of hanging rafters, based on a puff.
To increase the area of \u200b\u200bthe room, the lower edges of the rafters can be brought outside the house. In this case, they will not be attached to the Mauerlat, but to the ceiling, which, in turn, is held on the outer walls of the house with the help of the Mauerlat. The rafters are necessarily supported by struts. Racks go deep into the floor beams by no more than a third of their thickness.
This sloping roof truss system is different in that the upper triangles are made from layered, not hanging rafters. In this case, the puffs are supports for the uprights of the upper triangles.

Sloped roof calculation

Before starting work, two calculations must be carried out:

determination of the amount of necessary building materials;
calculation of the bearing capacity of the structure.

Determining how much material is needed is very simple due to the simple geometry of the sloping roof. Bearing capacity is not so easy to deal with. For its calculation it is necessary to take into account:

weight of the roof;
approximate mass of snow;
the mass of the crate;
mass of steam, hydro and heat insulating materials;
roof dimensions;
installation angles of slopes;
the installation step of the elements of the truss system and roofing sheathing;
additional load: mass of people and equipment, windows, ventilation, etc.

Based on these data and with the help of special programs, the bearing capacity is calculated. Depending on what load bearing capacity required, the cross-sectional area used in construction is selected wooden beam. If something does not suit you, the project can be corrected by changing the truss system, choosing a different roofing material, placing the rafters less often.

In most programs, the structure of a sloping roof can be visualized - it will be immediately visible on the 3D models how changes will affect appearance attic.

What materials need to be prepared?

After the development of the project, it will be clear which beam with which section should be used, which roofing material is better to choose, what should be the roof lathing. Will have to purchase big variety lumber: timber for the formation of Mauerlat, edged boards for the truss system, boards for battens. They need to be properly selected so that the design is durable and reliable.

Tips for choosing lumber:

coniferous woods - pine, spruce - are best suited for building an attic - they are strong and rigid enough to withstand the entire load;
wood should be well dried - its moisture content should not exceed 20%;
the material must be free of knots, cracks, traces of biological damage and other defects.

All before installation wooden elements sloping roofs are treated with flame retardants and antiseptics, as well as rotting impregnations. This treatment should be repeated periodically so that it is not necessary to replace load-bearing elements designs.

In addition to the main material, you need to stock up on metal fasteners for connecting the rafters to the Mauerlat and to each other, insulating and roofing materials.

Roof installation

Mauerlat installation

The construction of a sloping roof begins with the installation of a Mauerlat, to which the ends of the rafters will be attached. The nuances of this stage vary depending on the material from which the lower floor is built - if its walls are stone, you need to punch holes for anchors in them in advance and install fasteners. The spacing between anchors should not exceed 2 m.

Placed on the surface of the wall waterproofing material. Then the beam is marked, holes are drilled at the points of installation of the fasteners. Mauerlat is put on the anchor and tightly attracted with nuts.

Installation of floor beams

first, extreme beams are placed from the ends of the building;
strings are stretched between them to indicate the plane;
intermediate beams are installed.

Mounting racks

Racks must be set strictly vertically. The principle of operation is the same as in the case of floor beams - first, the extreme racks are mounted, then the intermediate ones in the same plane. The step between the structural elements should not exceed 2 m. The racks are fixed with temporary struts. The height of the beams is 10 cm more than the planned height of the ceilings.

Runs from edged board. The result should be a finished frame for the internal walls of the attic.

Installing puffs

The transverse beams are connected not to the racks, but to the girders, using metal roofing corners. If the width of the room is large, it is worth installing temporary spacers under each puff so that when walking on them during the construction of the upper slopes, the beams do not break or sag.

Rafter installation

First, the lower rafters are mounted. They are placed in the following order:

mounting points are planned on the Mauerlat - the step between them should be 1–1.2 m;
on the rafter legs the attachment points are cut according to the template;
first, the extreme rafters are attached, then, as before, intermediate ones along the twine;
struts are installed in accordance with the drawing.

The upper rafters are placed in the same way - according to the template. They are attached to puffs and interconnected; longitudinal connection with a ridge beam is required only if the length of the attic exceeds 10 m. Otherwise, you can get by with struts, with which the structure is broken mansard roof will be tough enough.

The last stages of work are the sheathing of the gables and the fastening of the lathing for the roof. Window openings should be left in the gables (at least 1/8 of the total area of the outer walls of the attic).

Structural insulation

On the finished frame, it remains only to lay the roofing cake. Its first layer is a vapor barrier, which prevents moisture from penetrating into the insulation. placed on a vapor barrier membrane thermal insulation material- it is recommended to use stone basalt slabs. They are laid in several layers with a shift in the joints, which will protect against the occurrence of cold bridges. The size of the plates should be several cm more step between the beams of the counter-lattice. So that the insulation does not sag and lose its performance characteristics, its density should be at least 35 kg / m 3.

From above, the insulation is covered with a waterproof membrane, which allows steam to pass through, but does not allow liquid moisture to penetrate into the room. A roof is laid on top of the waterproofing layer - the features of its installation depend on the chosen material.

After the installation of the roof, only the finishing touches will remain - the installation of drainage systems, decorative trim. Inside finishing material also attached to the crate over the thermal insulation. broken roof built. As you can see, it is quite possible to do it yourself - only the design and calculation will probably have to be entrusted to professionals.

Do-it-yourself sloping roof: truss system, photo

The first stage in the construction of a sloping roof is design and calculation ... In essence, a sloping roof is a residential attic, well insulated and protected from ...

Sloping roof - device, options, installation instructions

Owners of private houses consider every detail of their home: the type of foundation, facade decoration and the shape of the roof. The mansard sloping roof is one of the most popular designs of this part of the building.

Device

The truss system of a gable sloping roof is different from others large quantity fractures on slopes. It is considered to be one of the most beautiful forms, but, at the same time, and, like the hip, quite expensive. It is equipped for houses in which a residential or non-residential attic is planned.

Structural elements

Features of the truss system:

Unlike the classic gable roof, this model has special stiffening ribs. These racks provide strength to the roof and create smooth walls inside the attic;

Rafter system with headstock

A headstock must be installed between the hanging rafters and the puff. It guarantees tightening rigidity and creates additional support;

Scheme without headstock

In turn, struts are mounted between the uprights (they are also called contractions) and the layered rafters (which shape the roof). They are also stiffeners, but for the internal system of rafters - racks;
A broken half-hipped roof can also be hipped. The number of slopes depends on the height of the racks - the higher they are, the more kinks. A four-pitched roof is more convenient to use;

The difference between a gable and a four-pitched sloping roof

The angle of inclination cannot be less than 15 degrees. A single-pitched, two or more sloping roof must necessarily have a good slope for proper precipitation drainage. Otherwise, a house or extension with this type of roof will be constantly heated.

Experts recommend choosing coniferous wood as materials for the truss system of a private house. Such beams withstand sharp drops temperatures, resist moisture and snow, and also have excellent antiseptic properties.

Roof options

Types of broken roofs for private buildings:

Square. Here, a right triangle is formed between the layered rafters and racks. The internal section of the attic resembles a square, from where the scheme got its name. Perfect option for houses with a small area and the ability to equip a high attic. This option is ideal for a gazebo or a small frame house;

Square sloping roof design

Rectangular. This type of construction involves an increase in the eaves overhang due to wider slopes and floor beams. This option is suitable if the house has a large square. To prevent deformation of the layered rafters, the struts are strengthened with small racks. So arranged as residential buildings, and country, i.e., seasonal;

An example of a rectangular system

Combined. This scheme combines the design features of the previous ones. As additional supports, beams of props and layered rafters can be installed. The grandmother is often strengthened. The system is used for large residential attics. The main convenience of this design is strength, so that turrets or domes can be installed on the surface of the roof. In this way, a cottage or a country house with a veranda is often designed;
Three-sided and more. The nodes of the pediment in this design are additionally reinforced with special elements, because otherwise they may be deformed. The main difference between this design and the classic broken line is the presence of special fortified skating runs. Also here are diagonal rafters, which are much larger than the sloping ones. This type of construction is used for a brick building, a structure made of timber or blocks. Thanks to this installation scheme, you can make an interesting attic interior with a sloping roof.

Sloped roof attic interior

In addition, sloping roofs can be used for any utility rooms(garage, baths) and houses with built-in rooms (verandas, greenhouses, etc.).

Video: Mansard sloping roof

Before starting work, you need to make drawings of a sloping roof. Various options with a balcony, windows and other elements is freely available on the Internet, in dwg format, for example. It should be borne in mind that this is a modular design, its nodes require an appropriate connection. Brackets are used to attach the beams to each other. To calculate fasteners, you will also need a drawing and a technological map.

Sloped roof drawing with window Professional drawing example

Step-by-step instructions on how to make a sloping roof with your own hands:

First, the Mauerlat and floor beams are mounted. They will serve as the ceiling for the lower floor. Before installation, they must be treated with an antiseptic to protect against moisture and microorganisms;
A vapor barrier and waterproofing are installed under the wooden slope. These measures are needed to protect the ceiling from condensation from the house and possible moisture under the racks;
Depending on which layout is chosen, you need to think over the dimensions of the racks in advance. By default, they are 10 cm higher than required height ceiling, because after installing the truss system, internal finishing will be carried out;
It should be noted that the slope of the entire roof will depend on the size of the vertical racks. Therefore, select their height so that the roof is at an angle of 15 degrees or more. Otherwise, it will be difficult to drain liquid from it;

Step by step instructions with photo

Next, the racks are installed. Their construction involves the installation of vertical beams with temporary struts, which are removed after the installation of the top floor and headstock. Otherwise, the structure will be deformed and the roof scheme will be broken;
Floor boards are installed above the racks. To connect the upper floor and vertical beams, special corner braces are used. To install the headstock, the lower horizontal boards are additionally reinforced with crossbars. They guarantee the rigidity of the temporary installation;
After that, the required distance between the lower rafters is calculated. This can be done based on the material with which the roof will overlap, or using standard values. Experts recommend using a step of 1 meter if the area is large - 1.2. They must be built into vertical posts;
Laminated rafters should hang over the walls somewhat. This will help provide additional protection for a log house or foam blocks from the effects of rain and snow. At the end of the installation, the cornice is hemmed. To do this, you can use plastic siding for a log house, corrugated board or wooden boards;
When fastening is completed, temporary crossbars are replaced with permanent brackets.

The cost of installing a truss system by professionals varies from 1000 USD. e. up to ten. It all depends on the chosen design and size of the house.

Warming and finishing

After graduation installation work insulation and decoration of the attic with a sloping roof. Thermal insulation technology is similar to other types of roof structures. First laid on the beams vapor barrier film, waterproofing is laid on top of it. These surfaces are fastened with an overlap, installation is carried out using thin small nails.

Roof waterproofing

For insulation, pressed mineral wool, polystyrene foam, penoizol and other materials can be used. The installation of the heat insulator is carried out in such a way that when it is installed, the gaps between the beams remain visible - this will help with further finishing.

The sloping roof is finished depending on what material was chosen for the coating. Now ondulin is very popular - it perfectly tolerates temperature changes and exposure to ultraviolet rays. The cheapest and most affordable option is slate. But the easiest way to work on a sloping roof is with metal tile panels - this design requires constant trimming of the coating, but this is not necessary with tiles.

Do-it-yourself sloping roof: photo, video

Do-it-yourself sloping roof: device, options, installation. Warming and finishing. Broken mansard roof. Photos, videos, drawings.

How to build a sloping roof with your own hands?

A sloping or mansard roof is one of the most popular and common types of roofing. It is particularly efficient and convenient in the case when the attic involves the arrangement of a living room. The kink of the slopes provides significant additional space, while the upper level acts as a roof, and the lower one becomes the walls for the room.

A house with a sloping roof is quite common in our country. Similar type roofing is widely used both in covering private houses and in cottage construction. A frame house often happens with a sloping roof. This is due to the fact that the frame structure does not involve the construction of a large house, and the attic roof helps to maximize the space on the second floor to create another living room in the country house.

A broken roof is quite simple to build, although it requires special calculations in its design. With some experience, you can build it yourself. In the article we will look at how to build a sloping roof with our own hands.

Design

A sloping roof requires a preliminary calculation of all elements. The design is carried out in two stages:

The truss system of a house with a sloping roof is calculated adjusted for the weight of the finish coating. The calculation of the required amount of roofing is done by calculating the roof area. This roof represents four planes in the form of rectangles, its area will be equal to the sum of their areas.

Having calculated the area of the roofing material, it is easy to find out its weight and, in accordance with this, design a rafter system as capable of holding this roofing material. In addition to the weight of the roof itself, when designing the rafter system, it is necessary to take into account:

A lot of other elements of the roofing cake: insulation, insulating materials, battens;
The length of the rafter legs, the step of the truss system and the batten;
The slope of the roof slopes, the height of the ridge;
Temporary loads on the roof, such as the weight of builders, skylights (if they are planned), various fences and junctions.

The choice of the angle of the slope of the roof slopes is one of important points design, which is based on a number of factors:

Type of roofing;
Wind load and precipitation intensity of a particular region.

Classic slope angles broken roof located within the boundaries of 35-45 ° for upper tier and 60° for the bottom.

If you plan to add an extension to a house with a sloping roof, we recommend that this be included in your plan in advance. As a rule, such extensions are covered with a shed roof, which is, as it were, a continuation of one of the lower roof slopes.

If the design of the house assumes the presence of a roof with a balcony, then it is advisable to extend the roofing so that the balcony is under its slopes and is not exposed to destructive impact precipitation.

Material selection

After the completion of the calculation work, you can proceed to the selection of materials for the construction of the roof. Sloping roofs suggest a fairly standard approach to the formation of a roofing pie and choice building materials:

Mauerlat and girders are made of durable thick bars with a section of 200 * 200 and 50 * 100 mm, respectively;
Rafter legs are formed from bars 50 * 200 mm;
To create a counter-lattice and crate, boards of a smaller section of 50 * 50 or 20 * 90 mm will go;
To create a warm room under the roof, you will need a 200 mm thick insulation, as well as hydro and vapor barrier materials.

A broken roof and its strength depend not only on the accuracy of the calculations made and the choice of building materials, but also on the quality of the wood. We recommend choosing beams and boards of coniferous trees with a moisture content of no more than 20-22% without cracks and knots.

It is important to decide on the roofing material before starting installation work, since a number of important features of the truss system, such as the pitch of the rafters and battens, depend on its type. The mansard roof is compatible with any type of roof, as it has a fairly simple geometry and does not give a large waste of materials.

So how do you make a sloping roof? The construction of a mansard roof on your own requires compliance with a number of rules. Let us consider in more detail how to build such a type of roof step by step as a sloping roof with your own hands.

Installation of Mauerlat and truss system

The mauerlat beam is attached along the top of the walls to specially prepared studs. The optimal step between the studs is approximately 2 meters. Mauerlat bars are additionally attached to the walls with a wire tie. To protect the walls from moisture under the Mauerlat, it is necessary to lay a layer of roofing material.

The next step is to lay the floor beams, which will serve as a frame for the vertical racks of the truss system. The bars can be laid on the Mauerlat with fixing with iron corners or in recesses made in advance in the wall masonry.

Installation of the truss system begins with vertical rafters with level control. Further, runs with fastening with iron corners lie on the racks. Parallel racks are fastened together with puffs, which can be reinforced with struts for additional support.

The lower tier of the rafters has a Mauerlat and a run as its support. The rafters are pre-cut at an angle and attached to the support with plates. Strengthening of the lower rafter legs is carried out by struts, the lower edge of which is installed at an angle on the beam, and the upper one is mounted to the rafter with a bolt.

The upper rafters are also pre-cut according to the template. In the upper part, they are connected with boards or plates, and the lower part is inserted into the run with fastening with corners. The rafter legs are additionally reinforced with a stand to the place where the rafters are fastened and tightened.

Insulation, lathing and roofing

After the installation of the truss system, work is carried out on the insulation of the roof. Waterproofing with an overlap is laid on the rafters from the outside roll material 10-15 cm. The material is attached to the rafter legs with nails. Further work is moved under the roof. Layers of mineral wool are laid between the rafters and covered with vapor barrier material. The whole structure is sewn up from the inside with building cardboard under finishing interior space.

Outside, a counter-lattice is stuffed onto the waterproofing layer and then a crate with a step corresponding to the type of roofing material chosen.

The roofing material is laid in accordance with the installation rules for the selected type of roof, but in general terms it repeats the basic rules: laying from the bottom of the slope up.

We figured out how to make a broken roof on our own. If you follow our instructions, you will get a strong and reliable roof that will long years will delight you with its efficiency and convenience.

Do-it-yourself sloping roof

The basic rules for the design and installation of a sloping roof are considered. Information is given on the correct choice of materials, the intricacies of installing the truss system

Many owners of private houses, experiencing a completely understandable desire to get an extra residential floor at no particular cost, turn the attic into an attic. In this case, it is advisable to build a broken line instead of a conventional roof with straight slopes. How and from what such structures are built, we will tell in this article.

Types of broken roofs

A sloping roof differs from the usual one in that its slope consists of two planes:

the top is gentle;
the lower one has a slope of more than 45 o .

It looks as if an ordinary gable roof was taken by the middle of the slopes and stretched to the sides and up, thereby significantly increasing the volume of the attic space. But the increase in volume is only one of the advantages of such a solution. The second is the ability to make the roof higher. After all, its upper part, at the level of which the wind pressure is maximum, due to a small slope experiences less wind loads than regular roof with straight slopes.

The slope of the sloping roof consists of two planes with different angles of inclination

Distinguish the following types broken roofs:

Shed. It consists of only one broken slope, while the walls have different height. Such a roof is the simplest, but it is rare and mainly on extensions.
Gable. The classic version, which includes two broken slopes falling in different directions. The ends of the roof - gables - are vertical and represent a continuation of the walls.
Tri-slope. In this version, instead of the pediment, a third broken slope appears from one end. Such a roof looks more interesting and creates less stress on the foundation. end wall. The gable roof is asymmetrical, so it is mainly used on attached buildings.
Four-pitched (hip). There are no pediments, on all sides there are broken slopes. It is built on a separate building. The disadvantage is that the volume of the attic is reduced compared to the classic gable version. Advantages: spectacular architecture and minimal load on the foundation under the end walls.

Sloping roof slopes can be based on:

Walls.
Floor beams extended beyond the walls. This option is more difficult to implement, but it allows you to make the attic more spacious.

Along with the usual ones, there are broken roofs that have additional structural elements:

When constructing a sloping roof, a combined truss system is used. The upper flat rafters - they are called ridge rafters - are hanging, that is, they are supported only by the lower ends, and the upper ones are joined to each other. So that these rafters do not move apart under the influence of their own weight and snow load, they are connected by a horizontal element - a puff.

The side rafters are layered. They are supported both by the lower part - on the walls by means of a Mauerlat, and the upper part - by vertical racks.

In the rafter system of a sloping roof, both layered and hanging rafters are used at the same time.

Due to the simultaneous presence of both layered and hanging rafters, this system is called combined. In some cases, the side rafter has to be supported in the middle with a strut that rests against the base of the rack.

Racks, in turn, are supported by floor beams. If a attic floor made from concrete slabs, then to support the racks, a wooden beam is laid on it - a bed. Racks form the frame of the walls attic space, and puffs form its ceiling.

The sloping roof frame consists of rafters - hanging and layered - and additional elements that provide structural rigidity

Rafter attachment points

The reliability of the truss system depends on the correctly chosen method of fastening its elements.

Under the influence of the load, the hanging rafters will move apart, sliding along the surface of the beam or puff. To counteract slip, the following types of joints are used:

If the slope of the roof exceeds 35 o , a lock with a single tooth is sufficient for fastening.
The spike rests against the reciprocal tightening groove and does not allow the rafters to move apart
With more gentle slopes, a double tooth is used. To enhance the strength of the connection in the puff, two stops are cut out. One of them - extreme - is complemented by a spike. Under its size, an eye is cut out in the counterpart of the rafter.
For gentle slopes, the fastening of the rafter leg to the puff is usually performed using a double-toothed lock.
The most difficult node of a sloping roof is located at the intersection of the hanging rafter, puff and layered rafter. Therefore, it is reinforced with bolted joints.
A pair of bolts effectively counteract the torque at the rafter junction with tightening
The rafter leg is attached to the Mauerlat by means of corners and brackets. To facilitate installation and limit the movement of the rafter, a stop bar must be nailed to its lower surface.
Resistant board or bar, stuffed on the bottom edge of the rafter leg, do not allow it to slide down

Broken roofs with cuckoo, balcony, window

If the roof has a cuckoo, then its rafter system is mated with the main one. The cuckoo roof can be:

The presence of a "cuckoo" weakens the main truss system, in addition, careful sealing of the junction of different parts of the roof is required. Because of this, the design and construction of roofs with such elements is best left to specialists.

Balcony in the attic can be arranged in three ways:

To install a roof window, bars are fixed between the rafters, outlining the opening. They will play the role of a supporting contour for the window structure.

Cases are known when construction companies in order to expand the attic space, it was decided to modify the classical rafter scheme sloping roof, abandoning the usual arrangement of racks.

The technical solution is as follows:

As a result of strengthening the break point of the slope with overlays, a pair of rafters works as one curvilinear rafter leg.

Is it possible to make a sloping roof with a raised puff

The location of the puff is higher than usual - a technique that is sometimes resorted to when erecting a gable roof with straight slopes. But in the case of a sloping roof, a raised tightening device is not practiced, since in this case it is necessary to move the racks, as a result of which the attic room becomes less wide.

Calculation of the truss system of a sloping roof

To determine the dimensions of the rafters, you must:

To calculate the strength, you need to measure the angles of the rafters with a protractor.

Strength calculation

Today, the calculation of the attic roof truss system can be done using specialized software systems. But you need to be able to do it manually, because in field conditions the computer is not always available, and it will be useful to check the results before starting work.

To carry out calculations, you need to know the normative snow and wind loads characteristic of the construction region. These data should be sought in SNiP 23.01.99* "Construction climatology". According to this document in Russian Federation there are 8 zones with a standard snow load from 80 to 560 kg / m 2.

The map shows the standard values of snow load for each climatic region of our country

The value of the standard snow load can be taken from the reference table.

Table: normative values of snow load by region

region number	I	II	III	IV	V	VI	VII	VII
80	120	180	240	320	400	480	560

Actual snow load will depend on the slope angle. It is calculated according to the formula S \u003d S n * k, where S n is the standard snow load in kgf / m 2, k is the correction factor.

The value of k depends on the slope angle:

at angles up to 25 o k = 1;
for slopes from 25 to 60 o k = 0.7;
for steeper roofs k=0 (snow load is not taken into account).

Parts of the slope of a sloping roof have a different slope, respectively, and the actual snow load for them will be different.

Similarly, the territory of the country is zoned according to the magnitude of the wind load.

The territory of our country is divided into eight regions, in each of which the wind load has its own standard value

To determine the standard wind load, there is a reference table.

Table: normative values of wind load by region

region number	I a	I	II	III	IV	V	VI	VII
24	32	42	53	67	84	100	120

The actual wind load depends on the height of the building, its surroundings and the slope of the slope. The calculation is made according to the formula:

W \u003d W n * k * C, where W n is the standard wind load, k is a tabular coefficient depending on the height of the building and the environment, C is the aerodynamic coefficient.

Table: Correction factor for building height and terrain type when calculating the actual wind load

Height buildings, m	Terrain type
Height buildings, m	BUT	B	AT
Less than 5	0,75	0,5	0,4
5–10	1	0,65	0,4
10–20	1,25	0,85	0,55

Terrain types differ in the following ways:

Zone A - open areas where the wind does not encounter obstacles (coast, steppe/forest-steppe, tundra).
Zone B - areas where there are obstacles to the wind at least 10 m high: urban development, forest, relief folds.
Zone B - densely built-up urban areas with buildings within 25 m in height.

The aerodynamic coefficient C takes into account the angle of inclination of the slopes and the prevailing wind direction. It should be understood that the wind can exert not only pressure: at small slope angles, a lifting force arises, tending to tear the roof off the Mauerlat. To determine the coefficient C, you need to be guided by reference tables.

Table: values of the aerodynamic coefficient - the air flow vector is directed to the slope

slope slope, deg.	F	G	H	I	J
15	-0,9	-0,8	-0,3	-0,4	-1,0
15	0,2	0,2	0,2	-0,4	-1,0
30	-0,5	-0,5	-0,2	-0,4	-0,5
30	0,7	0,7	0,4	-0,4	-0,5
45	0,7	0,7	0,6	-0,2	-0,3
60	0,7	0,7	0,7	-0,2	-0,3
75	0,8	0,8	0,8	-0,2	-0,3

Table: values of the aerodynamic coefficient - the air flow vector is directed to the pediment

For those sections of the roof where there is a lifting force, the value of the coefficient C is negative.

Actual snow and wind load summed up and based on the result obtained, the section of the rafters is selected (taking into account their step and maximum length). Below is a table for softwood rafters premium(for other varieties, the values \u200b\u200bwill be different). Its cells indicate the maximum allowable length of the rafter with the appropriate section, step and load.

Table: the maximum allowable length of the rafters in accordance with the step of their installation and the amount of snow load

Section, mm
	100 kg/m2			150 kg/m2
	Distance between rafters, mm
	300	400	600	300	400	600
38 x 80	3,22	2,92	2,55	2,61	2,55	2,23
38 x 140	5,06	4,6	4,02	4,42	4,02	3,54
38 x 184	6,65	6,05	5,26	5,81	5,28	4,61
38 x 235	8,5	7,72	6,74	7,42	6,74	5,89
38 x 286	10,34	9,4	8,21	9,03	8,21	7,17

The installation of rafters with a pitch of 600 mm should be considered the best solution: with such a distance between the rafters, the rigidity and stability of the structure will be maximum, and for insulation it will be possible to use mineral wool or foam boards of standard width.

Video: attic calculation

Do-it-yourself sloping roof construction

The sloping roof refers to building structures of medium complexity. With certain skills and a few intelligent assistants, it is quite possible to build it with your own hands.

Selection of necessary materials

To build a sloping roof you will need:

Vapor barrier film - polymeric or anti-condensate with an inner non-woven textile layer.
Waterproofing. You can use special polyethylene film or the so-called superdiffusion membrane, which retains moisture, but at the same time allows steam to pass through.
Annealed wire with a diameter of 3–4 mm, which is used as fasteners when installing a truss system.
Other types of fasteners - bolts, nails, staples, special fastening plates with stamped teeth.
A steel sheet with a thickness of 1 mm or more - linings will be cut out of it for fastening the elements of the truss system.
Roofing material and self-tapping screws (nails) for its fastening.
Lumber.
Insulation - mineral wool, URSA (fiberglass), expanded polystyrene.

Rafters and other elements are usually made from the cheapest type of wood - coniferous. It should not contain rotted areas or traces of damage by bugs. All wood before installation of the truss system must be treated with antiseptics.

During the construction of the rafter system of a sloping roof, a pine beam and edged board are used without defects and damage.

The lumber you will need is:

for floor beams - a bar with a section of 150x100 mm, if the beams rest on external and internal load-bearing walls, or with a section of 200x150 mm when supported only on the outer frame of the building;
for the manufacture of Mauerlat - a bar with a section of 150x100 mm or 150x150 mm;
for racks - usually a beam of the same section is used as for floor beams;
for rafters - a board or timber, the cross section of which is determined by the above calculations;
for some fasteners and subfloor - unedged board different thickness;
for lathing - edged board with a section from 25x100 to 40x150 mm, depending on the step between the rafters and the type of roofing material;
for a counter-lattice - a board 50–70 mm thick and 100–150 mm wide.

The procedure for the construction of a sloping roof

The process of building a sloping roof is as follows:

Mauerlat is laid on the walls. Under the beam, you must first lay a waterproofing gasket made of roofing material.
Mauerlat is attached to the wall with the help of studs embedded in it, or anchor bolts(in this case, holes will have to be drilled in the wall) with a diameter of 12 mm. Fasteners should go into the body of the wall by at least 150-170 mm. Mauerlat can also be tied to a wall with annealed wire embedded in it.
For buildings made of concrete or building blocks, it is most convenient to mount the mauerlat on studs embedded in the armored belt when it is poured
Install floor beams. If the floors are supposed to go beyond the walls, they must be laid on the Mauerlat. Otherwise, the beams are laid on the walls through a roofing felt gasket and attached with corners or brackets to the Mauerlat.
They determine the middle of the floor beam and retreat to the left and right exactly half the width of the attic room - racks will be installed here.
The beam is baited with nails, and then set strictly vertically, using a plumb line and building level, and finally fixed to the floor beam with the help of corners and wooden linings.
Vertical racks are installed strictly vertically, and then connected with longitudinal runs and transverse puffs
Having installed both racks on the floor beam, they are connected at the top with a horizontal beam - a puff. Again, corners should be used for fastening.
Side rafters are installed on the sides of the resulting U-shaped structure. At the bottom, each rafter rests on the Mauerlat, for which it is necessary to cut a groove in it (the rafter). Fastening to the Mauerlat is carried out with brackets or corners.
The rafter leg is attached to the Mauerlat with brackets, corners and other special fasteners.
If the length of the rafter exceeds the maximum allowable, it is reinforced with a strut resting against the base of the rack. Also use additional racks and the so-called contractions.
For additional strengthening of the rafter legs, you can use struts, fights and additional racks.
The midpoint on the puff is determined: a vertical beam will be installed here - the headstock. Its function is to support the ridge knot, that is, the junction of the upper rafters.
Install the upper (ridge) rafters. In the ridge knot, they must be firmly attached to each other, for which it is necessary to use powerful bolts with washers or plates, or a steel lining.
The connection of rafter logs in the ridge part of the roof can be done end-to-end, overlap or half-tree
Install the grandmother in its place.
All truss trusses are assembled in a similar way. First, you should assemble the extreme trusses - then between their key points it will be possible to stretch the cord segments, which act as a guideline when assembling intermediate trusses.
Farms are fastened together with horizontal runs, which should connect the upper parts of the racks. Runs can be installed at an earlier stage, immediately after the installation of racks.
The finished rafter system is covered with a waterproofing film on top. As already mentioned, along with conventional polymer films, membranes are now being produced that are a barrier to water, but allow steam to pass through. AT different directions such a membrane acts differently, so it must be laid on the correct side (there are marks on the canvas). A roll of film is unwound in horizontal rows, moving from the bottom up, and the next row should lie on the previous one with an overlap of 150 mm.
The waterproofing coating is laid parallel to the cornice overhang with an overlap of 150 mm
Places of overlap are glued double sided tape. It is not allowed to stretch the film - it should sag by 2–4 cm. To prevent the material from slipping, it is fixed with a stapler (construction stapler).
A counter-lattice is stuffed along the rafters from above - boards 50–70 mm thick and 100–150 mm wide. This structural element is necessary to create a purgeable gap between the waterproofing and the roofing material - this will remove the condensate formed due to steam penetrating under the coating.
On top of the counter-lattice in a direction perpendicular to it, a crate is stuffed - boards, slats or solid flooring, the parameters of which depend on the type of roofing material and the calculated load.
The bars of the counter-lattice form ventilation gap, and the longitudinal rows of the lathing serve to fasten the roofing material
Roofing is attached to the crate.

Video: installing a sloping roof

Roof insulation is carried out after the completion of the installation of the truss system and the laying of the waterproofing layer. A feature of the broken roof is that the insulation is laid along the lower rafters and the ceiling of the attic room, formed by puffs. The upper triangle of the roof is left cold to ensure ventilation of the under-roof space.

Insulation plates should go into the gaps between the rafter joists with a noticeable tightness so that conditions for the formation of cold bridges are not created.

If an ordinary film was laid over the rafters as a waterproofing, there should also be a blown gap of at least 10 mm between it and the thermal insulation. If a superdiffusion membrane was laid, there is no need for a gap device.

Insulation boards are laid in several layers with offset joints in each row. A vapor barrier membrane is mounted on top of the insulation.

The roof is a multilayer structure consisting of protective films, insulation, roofing and ventilated gaps.

Video: insulation of a broken attic roof

https://youtube.com/watch?v=UqWyrNQ4eq0

The choice of roofing materials

It remains to decide how to cover the roof. There are quite a lot of roofing materials today, we present comparative characteristic the most popular ones.

Ondulin

In appearance, ondulin resembles slate, only it is multi-colored. In terms of internal composition, it is arranged quite differently: it is bituminous material, like roofing felt, only not cardboard is used as a base, but a rigid sheet of pressed cellulose. Ondulin costs a little more than slate, but still remains in the category of budget materials.

Disadvantages of ondulin:

lit;
has low strength;
short-lived;
in the heat it can spread a characteristic bituminous odor;
on the shaded side, like slate, it can become overgrown with moss, although manufacturers claim that this is impossible.

In addition to low cost and an extensive range of colors, the material has quite tangible advantages:

does not make "drum" sounds during rain or hail;
unlike slate, it is plastic, due to which it is more resistant to impact and can be used to cover roofs with a complex contour (“unbending” slate would largely go to waste);
is low compared to metal coatings thermal conductivity, so it does not heat up so much in the sun.

Decking

Today the professional flooring is one of the most popular roofing materials. "Profiled" in translation into everyday language means "wavy", only the waves of the corrugated board are not sinusoidal, like those of slate and ondulin, but trapezoidal.

Decking is produced in the form metal sheets with trapezoidal waves

Producing corrugated board from steel sheets, which are covered by double protective layer: first with zinc, then with a polymer. The material is very durable: the service life can reach 40 years. But keep in mind that a lot depends on the type of protective polymer, which is used as:

Acrylic. The least resistant type of coating. It is easy to damage during installation, it quickly burns out and can peel off after 3 years of operation.
Polyester. Most often used. In terms of cost-to-durability ratio, it is the best option for normal conditions, when there is no a large number pollution, and the roof is not subjected to intense mechanical stress. Polyester is applied in a layer of 20–35 µm, so special care must be taken during installation so as not to damage the coating.
Plastisol (PVC-based polymer). It is applied in a layer with a thickness of 175–200 microns, therefore it has an increased resistance to mechanical stress and tolerates the chemical aggression of a highly polluted atmosphere well. However, it is not designed for high temperatures and intense ultraviolet radiation, so it is not suitable for the southern regions. Another drawback is that it quickly burns out (in 4–5 years).
Pural. This polyurethane-based coating has appeared relatively recently. It is applied in a layer of 50 microns thick, it is characterized by resistance and to solar radiation, and to chemical attack, and to temperature changes. It also gives the material durability.
Polydifluorionad. Decking with such a coating is the most expensive, but it is also the most resistant. Designed for extreme climatic conditions or for chemically active environments. For example, it is advisable to cover buildings located on sea shore, or the structure of a chemical enterprise that produces emissions into the environment.

metal tile

Metal tiles, as well as corrugated board, are made of steel sheets with a polymer coating, only they are given a more complex shape that imitates the surface of ceramic tiles. It looks more impressive, but to give the desired shape, you have to use thinner steel, so the metal tile is inferior in strength to corrugated board.

The metal tile surpasses corrugated board in aesthetic qualities, and is inferior to it in strength and durability

The metal tile has the following advantages:

Light weight.
Profitability.
Aesthetics.
Resistant to fading and abrasion.

But this material has disadvantages that can upset the homeowner:

High level of sound transmission: during rain and hail, the house will be noisy.
A large amount of waste when covering roofs of complex shape.

Monolithic polycarbonate

A transparent roof made of monolithic polycarbonate is a rather exotic option. Warming in this case, of course, is not provided, so such a solution would be appropriate only in a region with a warm climate.

Polycarbonate as a roofing is mainly used on non-residential buildings, agricultural structures and buildings located in the southern regions

For fixation plastic panels on the rafters, a frame made of aluminum or steel profiles. When fixing polycarbonate, it must be borne in mind that this material changes greatly in size with temperature changes, therefore:

the diameter of the mounting holes should be 2-3 mm larger diameter self-tapping screws;
screws cannot be screwed in tightly.

Monolithic polycarbonate is different:

impact resistance;
small specific weight;
resistance to fire spread and fading;
inertness in relation to aggressive chemical elements;
ease of handling and cleaning.

At the same time, this material is unstable to small sharp objects and has a high coefficient of linear expansion when heated.

Soft roll roof

Traditionally, the following types of soft roll coatings are distinguished:

All these materials are produced on the basis of bitumen or bitumen-polymer mixture. They can only be used on roofs with a slope of up to 25 o - from steeper slopes, such a coating can slip in the heat. Not so long ago, new varieties of soft roofing have appeared, the raw materials for which are rubber and petroleum resins. They can be laid on slopes of any steepness and, unlike bituminous ones, they tolerate the impact of negative environmental factors well (the service life is 25 years) and are laid in one layer (bitumen-containing materials are laid in 3–5 layers).

We also produce such materials - these are Rukril and Cromel membranes. The width of the roll can be up to 15 m, so there will be very few seams in the coating.

The membranes are attached either with special glue or with self-tapping screws.

As can be seen from the drawings and diagrams, a sloping roof allows you to use the attic space with maximum benefit. But at the same time, it surpasses the usual pitched roof in complexity both in calculations and in implementation. Therefore, in the absence of sufficient experience, it is advisable to entrust its design and construction to a specialized organization.

Its peculiarity is in dividing the slope into several planes, which makes it possible to use the space under the roof for an attic device. Having a room under the roof will reduce the overall heat loss of the house. Do-it-yourself sloping roof can be properly built only if there are competent calculations and following all the standards during construction.

How to choose the angle of inclination

When choosing the angle at which the roof slopes are installed, it is necessary to consider:

type of roofing;
rainfall and wind strength;
purpose of the room - for living quarters, the height of the ridge should not be placed below 2.5 meters.

The optimal value for the upper slopes is 30-45 degrees, for the lower - 60 degrees.

Drafting a project

Any construction begins with a drawing, and such a complex structure as a sloping roof will require drawing up detailed diagram with all sizes and calculations. You can start work by viewing photos and diagrams that will help you understand how to build a sloping roof structure. Knowing the dimensions of the building, the type of roofing and insulation material, it is possible to calculate the dimensions of the components for the truss system using special calculators.

The consumption of material for roofing, as well as waterproofing, is calculated by the size of the roof area, which is calculated by adding the value of all slopes. The insulation layer for the mansard roof should be at least 20 cm.

Material

Before you make a sloping roof, pick up quality material for its construction. For this, dry glued laminated timber is purchased, the moisture content of which is 18–22%. Before installation, it undergoes mandatory treatment with an antiseptic and a means of preventing combustion. The treatment with the compositions is carried out in an open space, the funds are applied in two layers.

timber for Mauerlat 200 × 200 mm, for struts 50 × 100 mm;
board 50 × 150 mm;
unedged board;
metal brackets, corners, bolts, nails, self-tapping screws;
laths for lathing 25 × 50 mm;
vapor barrier membrane, insulation, waterproofing;
roofing material.

Construction stages

Mauerlat. Installation of the truss structure is expected at the stage of wall construction. In the upper row, special studs are laid for the subsequent fastening of the Mauerlat, which is the basis of the roof. This timber is laid around the entire perimeter of the walls, prepared studs are inserted into the drilled holes and tightened with nuts. The step of the studs is two meters, the best option is if they are located between the rafters. A roofing material is laid under the Mauerlat, which provides protection from moisture. To securely hold the structure, a wire harness is used.

Beams. A thick beam with a section of 200 × 200 mm is laid directly on the mauerlat or in special pockets left in the masonry walls. The edges of the beams located on the masonry are smeared with mastic. The beam will serve as a support for vertical racks. They are attached to the Mauerlat with metal corners. Requires strict adherence horizontal level in order to obtain a high-quality basis for the roof. You can change the position of the beam by placing boards.

Installation of rafters. The vertical stops on the gables are the first to be exposed. Their level is controlled by plumb lines. Racks are temporarily fixed with spacers. A cord is pulled between the exposed rafters and all remaining racks are installed in increments equal to the location of the beams. Runs from the board are laid on the racks, their fastening is carried out with corners and self-tapping screws. On top of the runs, longitudinal puffs are attached, connecting the parallel racks and completing top harness. Until the final installation of the remaining rafters, the puffs are supported by struts.

The lower rafters are installed based on the run and Mauerlat. To facilitate the work of preparing the bars, a template is pre-executed. A thin board is applied to the run and sawing is performed at the desired angle. All lower rafters are cut according to the pattern and installed. The lower part, lying on the Mauerlat, is cut out on the spot. For fastening, plates or corners are used, twisting them with self-tapping screws or hammering them with nails.

Before installing the upper hanging rafters, it is necessary to mark the center of the roof. To do this, use a temporary rack, fixed in the center of the Mauerlat and gable puff. The top edge of the board will mark the center of the roof. A basis for the template is applied to this board, according to which the upper rafters will be cut, the second edge of the workpiece rests on the run.

All top rafters have same size, so they are filed in one pattern. The upper ends of the rafters are connected with board scraps, plates or bots. The lower part is inserted into the run with a cut and fastened with corners. Each rafter leg is supported by a 25 × 150 mm hanging rack, which is attached to the rafter junction and to the puff.

The lower rafters are reinforced with permanent struts. To do this, use a board 50 × 150 mm, the lower end is cut at an angle and mounted on a beam, the upper end is attached to the rafter with a bolt or stud. Having installed all the struts, remove the temporary supports.

After the installation of the roof structure is completed, it is necessary to correctly lay all the layers of the roofing cake. Initially, the rafters are sheathed vapor barrier membrane starting from the bottom of the roof. The joints of the material are glued with adhesive tape. Then the insulation is laid. Air vents must be installed between the roof insulation layer to ventilate the space. Low quality ventilation will cause condensation and dampness. Roofing should be selected taking into account its thermal insulation qualities, so the use of metal is not desirable. As a heater, choose safe non-combustible materials that are not exposed to moisture. Such materials include expanded polystyrene and foam glass. After insulation, waterproofing is installed.

The lathing is carried out directly under the selected type of roofing. A house with an attic

The popularity of sloping roofs is due to the cost-effectiveness of construction and the ability to rationally use the attic space. They are used to organize insulated and non-insulated attics. The technology for the construction of roof structures with a variable angle of inclination of the slopes differs from the traditional two-slope scheme.

Therefore, those who want to acquire an attic floor and successfully prove themselves in the field of a roofer need to know how the broken roof truss system is arranged and how the dimensions of the materials for its construction are calculated.

The brightest and most expressive representative of the class of broken roofs is a pentagonal design with a clear difference in the angles of inclination of the slopes. Even without delving into the specifics of its construction, one can understand that it is made up of two tiers stacked on top of each other. In the lower solid tier there is an attic, which gave the second name to broken roofs. A less voluminous top tier, crowning the lower part, determines the shape of the structure in the region of the ridge.

Briefly about the specifics of the rafter structure

The truss frame for both parts of the mansard roof is built according to the rules dictated by the usual one. The lower part of the sloping roof frame is built by installing layered rafter legs. In the device of the upper part, both layered and hanging rafters can be used. The bottom of the layered rafters has the right to rely on the Mauerlat or on the floor beams. The support for the top is most often a wooden frame, which at the same time plays the role of a frame for one of the walls of the attic. In the device of the upper tier, they are mainly guided by the convenience of work for the performer.

By tradition, the angle of inclination of the slopes of the lower part of the sloping roof is much steeper than the upper one. It is they who create a break - a clear indicator of the use of broken technology in the construction of the roof. However, the steepness of the upper and lower parts of the slopes may be equal, which is why broken structure it will look like a normal duo. But they stand by the standard method for broken roofs, because the frame of the lower tier must provide the possibility of organizing the exploited space. Those. truss system must have necessary elements with a given bearing capacity for the construction of walls and ceilings of an insulated or cold attic.

Types of loads and their combination

We will not give sophisticated formulas according to which the rafter system of a sloping roof is calculated by designers of construction enterprises. Builders know them even without us. Those who decide to build one or two roofs on a suburban area do not need such fundamental information at all. There are plenty of programs on the Internet that perform complex mathematical operations in a couple of seconds to calculate the cross section of rafters, supports and beams. It is better to analyze what data is required to be entered into the program, as well as what types of loads on the floor, the rafters of the upper and lower tiers should be taken into account.

Download the program here -(only Excel is needed for work). Further we will give examples of working specifically with it.

Why limits are needed

Each element of the rafter system of a sloping roof will be affected different kinds loads. The sum of the loads should not lead to deformations and damage requiring mandatory repairs. Bearing structures according to the rules, they are calculated taking into account two limit values, these are:

Ultimate strength - a state, the excess of which leads to the destruction of the building structure, to the loss of endurance or stability.
Ultimate deformation is a state, the excess of which leads to unacceptable deflections, as a result of which not only the geometry of the structure changes, but nodal joints are violated.

For both types of specified limit states, designers perform calculations. An independent roofer does not really need these subtleties. In the calculation programs available on the Internet with the formulas embedded in them, the limits are already taken into account. They are introduced into the calculation algorithm in the form of signal values of the type:

N tr. strength - the size of the element of the truss system, the reduction of which will lead to a state of loss of strength.
N tr. deflection - the size of the element, the reduction of which will lead to a threatening deformation.

When referring to automatic computational assistance, such values must be paid close attention. This is an extreme minimum indicating that the actual design values should be higher.

The list of loads acting on the roof includes the weight of winter precipitation, wind force, own weight, weight of furniture and people operating the attic. Loads can act simultaneously, alternately or in any combination such as snow + furniture + people; snow + wind, etc. Calculations are carried out to the maximum in an effort to provide for the likelihood of exposure to the greatest load.

How to determine the weight of the snow cover

To determine the weight of the snow cover, special knowledge is not needed. It is carried out by finding out whether the construction site belongs to a specific "snow region". We found a region on the map with a number assigned to it, then looked at the plate how much snow would press on a horizontal surface.

For the rafters of the upper and lower tiers of a sloping roof, the snow weight indicators will be different. The slopes of a sloping roof in most cases are unequal in slope. Solid precipitation has more opportunity to linger and lie down on a close to gently sloping top than on the steep slopes of the lower part. It should be noted that on slopes with a steepness of up to 30º, the weight of snow is taken equal to the unit of the average statistical value adopted in the region based on long-term observations of the meteorological service. It is believed that on slopes with a steepness of 60º or more, snow does not linger at all, i.e. equals zero. The value of the snow weight in the interval between the indicated slopes is found by interpolation. For example, if the angle of inclination is 45º, then the tabular indicator should be multiplied by a factor of 0.5, for 50º by 0.33, etc.

How to find the wind load

Wind load is needed to calculate the stability of the truss system. To determine it, we again use a zoning map, but already compiled according to wind pressure values. This indicator is necessary for the rafter legs of both tiers of the roof, because the gusty wind can tear and blow away the flat part, and overturn the steep part. The information on the wind strength determined from the map is corrected by multiplying by a coefficient developed for different types of terrain.

In regions with high wind load, the frequency of attaching rafter legs to walls increases, i.e. they are fastened with wire twists more often than through one. For stability, the number of wind ties increases - struts, supports, boards or slats nailed to three or more rafters. Their weight must be taken into account when calculating total weight roof structure.

Roof mass load

The weight of the roof is a prefabricated characteristic with individual parameters. In fact, this is the mass of a roofing cake of a specific insulated or cold design With a certain kind coverings and a solid or sparse crate specially arranged for covering. It is calculated per meter of roofing area.

The average weights of the coatings can be found on the plate. It should be noted that when using relief roofing materials, the weight of the snow cover should be increased by 10%. For example, if corrugated board with a large wave is produced, it should be remembered that the snow cover in the recesses can accumulate and lie for a long time.

The weight of the crate depends on the type of coating. The device of a soft roof requires a continuous flooring from a board, sheets of moisture-resistant plywood or OSB boards. Profiled tin, slate, clay tiles are mounted on bars installed with a certain step. The weight of the crate will be increased by installing diagonal wind braces in regions with high wind load. The mass of insulation and the rafter system itself with struts, supports, girders and other elements is also calculated individually.

For preliminary calculations There are indicative averages:

the weight of the wooden crate is from 10 to 12 kg / m²;
weight of layered rafter legs with a run from 5 to 10 kg / m²;
the weight of the hanging legs of the truss truss is from 10 to 15 kg/m².

The readings calculated using the programs should not differ too much from the figures given. For insulated attics, the list of loads should be supplemented with the weight of the sheathing. In the case of using a heater with a thermal conductivity coefficient not much different from 0.04 W / m × ° C, its mass can be neglected.

We have shown where and how to find values to be entered into settlement systems. All other information for the mathematical determination of the cross section of the rafters, beams, supports is entered according to the design data. If the calculation system warns that "the condition is not met" or the bearing capacity is not provided, the dimensions of the elements should be increased.

Construction of a broken truss system

Before proceeding with the installation of a truss system for a future sloping roof, it is necessary to make a project and make calculations of structural elements. We will assume that the design stage has been passed.

Consider one of typical examples attic structures with two tiers of layered rafters hoisted over a brick box. We will fasten the rafter system to the Mauerlat - a wooden frame made of timber 150 × 200mm, laid flush with the inner perimeter of the walls. A row of bricks was laid along the outer edge of the box, masking the mauerlat and removing part of the spacer load. The upper plane of the Mauerlat should be 2-3 cm higher than the brick strapping.

Installation of floor beams

We begin the construction of the ceiling with the installation of extreme beams, the removal of which determines the width of the cornice overhangs. Further, along the cord stretched between the extreme beams, we install intermediate elements with a step equal to the distance between the rafter legs. For insulated roofs, it is recommended to make the step equal to the width of the thermal insulation plate so that the insulation sits tightly in the inter-rafter space intended for it. For non-insulated structures, the step is calculated so that an integral number of truss trusses with the same distances between them fit.

The size of the beam for the construction of the ceiling is 100 × 200mm. When laying the beams, we align their upper plane, if it is not possible to set it to a strictly horizon. Alignment is done by trimming the Mauerlat or lining wood chips under the beam. After attaching the beams to the Mauerlat, we attach a short beam to their end, so that they form a plane for the end cornice overhangs. The spacing between the short beams doesn't matter, maybe 1m or so.

Construction of the walls of the attic

We mark on the arranged ceiling the lines of the location of a number of supports for the rafter legs of the lower tier. Simultaneously with the supporting function, they play the role of a frame for the walls of the attic.

We act as follows:

We install corner supports, for the manufacture of which we use a bar 100 × 150 mm long 10 cm more than the final height attic ceiling. We check the verticality of the supports with a plumb line, we will fix it only after we make sure that the installation is flawless. For stability, we fix their position with temporary braces. By analogy, we mount the supports in the middle of the gable walls.
We connect the corner supports with a cord to indicate the installation location of the intermediate racks. For the manufacture of intermediate supports, material 50 × 150 mm with a height equal to the corner supports is suitable.
On top of two rows of supports we lay runs made of boards 50 × 150mm. Temporary spacers will no longer be needed, the walls of the future attic built are stable even without them.
We install a board on the runs with an edge, it will form the ceiling of the attic.
On top of the ceiling of the attic under construction, we lay a board 25 × 150mm. It does not need to be installed along the axis of the building. It is better to lay in parallel, stepping back from the axis of 20-30cm.

The result of the efforts made is the finished frame of the attic and supports for installing the upper tier of rafter legs.

Installation of rafters of the lower tier

The rafters of the lower tier of a sloping roof are manufactured and installed using the standard layered method:

We apply a board 25 × 150mm of the required length to the end of the structure being constructed and, in fact, mark the lines of the upper and lower washed down with a pencil. This is a template that can be used to make all the rafters of the lower tier, if there are no deviations in the geometry of the truss system.
If there is any doubt about the impeccability of the previous work, we install only the extreme legs and pull the lace between them. According to the template on the remaining rafters, we only make the top washed down. We will mark the bottom line after the fact, combining the upper plane of the workpiece with the cord guide.
We install rafter legs. We fasten them to the floor beams with brackets or metal corners, and at the top to the girders with two or three nails.

It happens that to cover the lower slope along the entire length, one board is not enough. In such situations, the rafter is mounted from two short boards sewn with a trim of material of a similar section with a length of 1 m or more. True, it is still advisable to order lumber of the required length so as not to weaken the structure with stitched sections.

Installing the rafter legs of the upper slopes

For the manufacture and installation of the upper rafters, you must first mark the central axis. To do this, a piece of inches should be nailed to the extreme ceiling board of the attic strictly vertically. One of the trimming edges must exactly match the central axis of the sloping roof truss system indicated on the diagram, further:

We try on an inch to the end for the production of a template and mark on it the lines of cuts, the upper of which we draw straight along the axis indicated by the trim.
We make a pair of rafter legs of the upper slopes according to the template. If we do not doubt the geometry of the constructed frame, we make several blanks at once. Otherwise, we proceed in the same way as with the lower brothers.
We install the first pair of rafters, calling for assistance from two pairs of working hands. You can’t cope with the installation alone, because they don’t have an upper support. So that the newly erected truss truss does not fall, we support it with a strut.
We mount the remaining roof trusses of the upper tier. We prop them up with struts after 3-4 pieces. The angle of inclination of the struts must be more than 45º. The direction of their inclination should be alternated.

Note that in order to prevent stretching and deflection of the attic ceiling boards, each upper truss truss must be equipped with a hanger from a board of approximately 25x150mm.

The photo selection will acquaint you with the specifics of the nodal connections of the broken-type roof truss system:

Along the line of the ridge and the lines of the fracture of the slopes, the crate is made continuous, regardless of the designed type and step of its installation. Two boards are nailed across the direction of the rafter legs with a gap of 2-3 mm between them. A similar continuous flooring is arranged in the valleys, if any, around the dormer windows and holes for driving the chimney pipe. In the case of using soft varieties of roofing, the crate is arranged continuous over the entire area of \u200b\u200bthe slopes.

If the thickness of the insulation is equal to or greater than the width of the rafter, a counter-lattice is arranged in front of the batten, which is constructed by installing a remote bar. It is necessary to form a gap between the waterproofing and the roofing material. Nail the spacer bar with outer side systems to the edge of the rafter. If the thickness of the thermal insulation boards allows you to leave the ventilation gap without remote tricks, there is no need to install a remote bar. It is also not needed in the construction of an insulated roof.

Upon completion of work on the installation of the truss system, cornices, gable walls, called tongs in wooden housing construction, are sheathed. Short overhangs adjacent to the gable walls are equipped, after which it is time to lay the roofing.

Video selection for independent builders

For those who wish to visualize the process of building a sloping roof, three videos with step by step production works:

It is impossible to consider all options for the construction of roof structures for broken roofs within the framework of one article. Roof types, architectural parameters, regions differ. There are many nuances used in specific conditions construction. However, the examples we have given perfectly demonstrate the general technological principle. This information about the calculation rules and construction schemes should help both home craftsmen and owners who control the work of a hired team. Leave your questions, if any, in the comments.

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What parts does a broken attic consist of?

In essence, a sloping roof is a residential attic, well enough insulated and protected from moisture and noise to make it comfortable to live in. Therefore, in terms of design, it differs slightly from an ordinary gable roof.

The following main elements of a sloping roof are distinguished:

vertical racks;
puffs - horizontal beams;
rafters - stiffeners, which are the skeleton of the entire structure;
struts - diagonal beams supporting the rafters;
mauerlat - wooden beams with special fasteners connecting the structure to the walls of the house;
ridge run- a set of upper elements of the truss system;
grandmas - fasteners that ensure the rigidity of the hanging rafters;
contractions - horizontal struts that remove part of the load from the rafters;
crate - a frame for fastening roofing material and insulation;
roofing - can be made of ceramic tiles, different types of slate, profiled sheet and many other materials;
heat, hydro and sound insulation.

Thus, the whole construction consists of a set of right triangles. They are connected to each other with wooden beams. All the elements described are easy to find on the drawing of a broken attic.

Technical requirements for sloping roof

Sloped roofs are subject to the following requirements:

the height of the attic walls must exceed 2.2 m;
good ventilation must be provided so that moisture does not condense under the roof;
roofing material should have a small mass;
the design must provide for measures against the impact of additional load on the truss system - that is, the roof elements must withstand not only their own weight, but also, for example, snow;
the attic loses heat faster than the lower floors, so special attention should be paid to thermal insulation;
to ensure fire safety, all wooden beams and batten elements should be treated with flame retardants.

Varieties of truss systems

Based on the design features of the attic, such types of mansard broken roofs can be distinguished.

Two types of rafters are used: hanging and layered. The attic floor beams are installed, a little short of the edges of the walls of the lower floor. The lower slope is made of layered rafters, which are attached to the walls of the house with the help of a Mauerlat. The frame of the attic walls is made from the racks. Such triangles are installed along the walls and connected by contractions. From above, they are joined by triangles of hanging rafters, based on a puff.
To increase the area of \u200b\u200bthe room, the lower edges of the rafters can be brought outside the house. In this case, they will not be attached to the Mauerlat, but to the ceiling, which, in turn, is held on the outer walls of the house with the help of the Mauerlat. The rafters are necessarily supported by struts. Racks go deep into the floor beams by no more than a third of their thickness.
This sloping roof truss system is different in that the upper triangles are made from layered, not hanging rafters. In this case, the puffs are supports for the uprights of the upper triangles.

Sloped roof calculation

Before starting work, two calculations must be carried out:

determination of the amount of necessary building materials;
calculation of the bearing capacity of the structure.

weight of the roof;
approximate mass of snow;
the mass of the crate;
a lot of steam, hydro and thermal insulation materials;
roof dimensions;
installation angles of slopes;
the installation step of the elements of the truss system and roofing sheathing;
additional load: mass of people and equipment, windows, ventilation, etc.

Based on these data and with the help of special programs, the bearing capacity is calculated. Depending on what bearing capacity is required, the cross-sectional area of the wooden beam used in the construction is selected. If something does not suit you, the project can be corrected by changing the truss system, choosing a different roofing material, placing the rafters less often.

In most programs, the design of a sloping roof can be visualized - on the 3D model, you will immediately see how the changes will affect the appearance of the attic.

What materials need to be prepared?

After the development of the project, it will be clear which beam with which section should be used, which roofing material is better to choose, what should be the roof lathing. You will have to purchase a wide variety of lumber: timber for forming a Mauerlat, edged boards for the rafter system, boards for battens. They need to be properly selected so that the design is durable and reliable.

Tips for choosing lumber:

coniferous woods - pine, spruce - are best suited for building an attic - they are strong and rigid enough to withstand the entire load;
wood should be well dried - its moisture content should not exceed 20%;
the material must be free of knots, cracks, traces of biological damage and other defects.

Before installation, all wood is treated with flame retardants and antiseptics, as well as impregnations from decay. Such processing should be repeated periodically so that the load-bearing structural elements do not have to be replaced.

In addition to the main material, you need to stock up on metal fasteners for connecting the rafters to the Mauerlat and to each other, insulating and roofing materials.

Roof installation

Mauerlat installation

A waterproofing material is laid on the surface of the wall. Then the beam is marked, holes are drilled at the points of installation of the fasteners. Mauerlat is put on the anchor and tightly attracted with nuts.

Installation of floor beams

Installation sequence:

first, extreme beams are placed from the ends of the building;
strings are stretched between them to indicate the plane;
intermediate beams are installed.

Mounting racks

Runs from edged boards are installed between the racks. The result should be a finished frame for the internal walls of the attic.

Installing puffs

Rafter installation

First, the lower rafters are mounted. They are placed in the following order:

mounting points are planned on the Mauerlat - the step between them should be 1–1.2 m;
on the rafter legs, the attachment points are cut out according to the template;
first, the extreme rafters are attached, then, as before, intermediate ones along the twine;
struts are installed in accordance with the drawing.

The upper rafters are placed in the same way - according to the template. They are attached to puffs and interconnected; a longitudinal connection with a ridge beam is required only if the length of the attic exceeds 10 m. Otherwise, struts can be dispensed with, with which the construction of a broken mansard roof will be quite rigid.

Structural insulation

On the finished frame, it remains only to lay the roofing cake. Its first layer is a vapor barrier, which prevents moisture from penetrating into the insulation. A heat-insulating material is laid on the vapor barrier membrane - it is recommended to use stone basalt slabs. They are laid in several layers with a shift in the joints, which will protect against the occurrence of cold bridges. The size of the slabs should be several cm larger than the spacing between the beams of the counter-lattice. So that the insulation does not sag and does not lose its performance characteristics, its density must be at least 35 kg / m 3.

After the installation of the roof, only the finishing touches will remain - the installation of drainage systems, decorative trim. Inside, the finishing material is also attached to the crate over the thermal insulation. Sloping roof built. As you can see, it is quite possible to do it yourself - only the design and calculation will probably have to be entrusted to professionals.