Do-it-yourself installation of a sloping roof. Sloping roof: features and device of unusual design

A sloping roof differs from a gable structure by installing rafter legs in two levels. The following selection of broken roof videos will help you understand the technology for creating such truss system from two levels.

Sloping roof on the bath

Here you will see the construction of a sloping roof on a log bath. The workers first installed the inner supports and rafters of the lower tier. This was followed by sheathing of the truss system and gables. Only after that the team began to install the rafters of the upper part.

Sloped roof rafters for a house made of timber

The next video shows step-by-step instruction for the assembly of the truss system. First of all, you need to install a support beam of the required length, taking into account overhangs. Look carefully at how you need to connect the two parts of the support beam. Pay attention to the location of the docking bar. It must be inside the house.

In the second part of the video, you can watch the installation of the truss system on the house. First of all, a sheathed front gable is installed. Then the remaining elements of the system and the rear sheathed gable rise.

We make roof overhangs correctly

In the following video, you will see the installation instructions for the roof overhang.

Would you like to learn how to independently design a mansard sloping roof? Answers to many questions are given in the next video. Using the recommended program, you can independently develop a sloping roof project for your home.

Sloped roofs are among the most popular and most effective roof structures. The construction and arrangement of such a roof requires the contractor to have certain skills to perform the necessary calculations and related activities.

However, having understood the main provisions of the manual, it will be possible to cope with the arrangement of such a roof structure on its own without involving outside specialists which will result in significant savings.

A sloping roof is perfect for those situations where the arrangement of a residential attic is planned. In this case, the roof space will have fairly high ceilings.

It is somewhat more difficult to build a sloping roof than an ordinary one- or two-slope structure, but, as you already know, there are no impossible tasks.

Broken roofs look best on buildings that have a square shape. If your house is narrow and long, there will be practically no benefit from the attic, and therefore from the roof structure in question.

Any roof structures, and the broken line is no exception, are calculated in two stages. When performing the first calculation, the required amount of finishing material is set, and the second calculation is designed to establish the bearing capacity of the rafters.

Drawing - Dimensions mansard roof

The first calculation is performed using the values of the geometric dimensions of the roofing system. The calculation of the bearing capacity of the rafter system is somewhat more complicated. When performing it, the following indicators must be taken into account:

Having received all the above data, you will be able to calculate the rafter system using the appropriate formulas or special programs, which is easier, faster and more convenient.

Based on the results of the calculations, you will determine whether the sections of structural elements are specifically suitable for your roof structure. If necessary, the characteristics of the crate and rafter legs can be changed. You can also replace the roofing material.

For maximum convenience, create a three-dimensional model of the future broken roof structure with the parameters you have chosen. Special programs will help you with this.

What is the roof made of?

After completion of all calculations and preparation of the necessary project documentation, you will know what the cross section of the elements of the roof truss system should be, which crate is best to equip and which roofing material is suitable specifically for your case.

Go get the necessary supplies.

First of all, buy a beam for arranging the Mauerlat, as well as beams or boards for mounting the batten and an edged board for the rafter system. Also, rafters can be made from timber.

Pine wood is ideal. It is important that the moisture content of the material does not exceed 20-22%. The material should not have large knots. Traces of damage by bugs and bluish spots should also be absent.

Consider the fact that the strength, reliability and durability of a broken roof structure directly depends on the quality of wood.

Before using the purchased material for its intended purpose, be sure to treat it with an antiseptic preparation. Special funds protect the material from decay. Also, periodic treatment with antiseptics will need to be carried out during the entire period of use of the roof structure.

In addition to antiseptics, all wood must be treated with flame retardants - these are special fire-fighting agents.

Process the material outdoors or in a well-ventilated area. Be sure to wear protective gloves and a respirator. The funds mentioned are applied double layer. For application, it is most convenient to use a sprayer, ordinary brushes are also suitable.

After applying the impregnations, let them dry completely, and only then proceed to the other planned activities.

Also, for arranging a broken roof structure, you will need fasteners - self-tapping screws, plates, bolts, etc.

Additional purchase suitable materials for waterproofing, insulation and vapor barrier structures, as well as finishing roofing material.

Roof erection procedure

The arrangement of the considered structure is carried out in a few simple steps.

First step

Fasten the Mauerlat to the top strapping beam.

Second step

Install the rafter legs according to your design drawings. Pre-cut the templates for connecting the truss elements with the support beam (Mauerlat).

Third step

Set up vertical racks and fix them on the floor beams. They will take on the function of the frame of the walls of the future roofing space.

At the top, tie the racks with girders. These elements will simultaneously take over the functions of puffs for the upper truss elements and ceiling beams for attic room.

Perform further work according to the requirements of your project. At the same time, be sure to keep in mind that the rafters, due to which a sheer roofing bevel is formed and the upper rafter legs with a Mauerlat are tightened, must be layered. The upper rafters in the construction of such a roof will be of the hanging type.

For additional rigidity of the hanging rafter legs, provide fixation on the pasterns. They must be connected to puffs that act as ceiling beams of the attic floor.

If necessary, install spacers and struts. All listed structural fasteners should be initially marked on your roof drawings.

On the extreme rafters placed from the ends of the house, install additional frames to accommodate the gables, doorways and double-glazed windows.

Insulation work and finishing

In conclusion, it remains to lay the necessary insulating materials. First fasten on the frame of the roof structure vapor barrier film, laying it on the rafter legs and fixing it with a stapler. Fasten the film with an overlap, without excessive sagging.

Mount the crate from the timber. Select the step of the crate individually in accordance with the features of the chosen finishing coating. In some situations, a metal profile is used to equip the crate, but the option using a wooden beam is the most common.

Lay down thermal insulation material(best minvatu) between truss elements. Place the heater in the spacer. From the side of the attic room, additionally fix the insulation with a crate. In the future, the finishing internal coating will be fixed to it.

Lay down waterproofing material. The principles of laying and fastening are the same as in the case of vapor barrier membrane. Proceed to laying the finishing material on top of the equipped moisture insulation. The slopes of the considered design are based on a broken profile, therefore top coat should be mounted from below.

At the joints of the roof slopes, lay the top row of finishing material so that it overlaps the lower tier and creates a kind of visor above it.

Roofing on mansard roof

In conclusion, it is necessary to install various additional elements of the roof structure, such as gutters, fences, etc.

A finished broken roof structure, created on its own, is in no way inferior to similar buildings equipped with the involvement of professionals.

Successful work!

Video - Do-it-yourself sloping roof

Many owners of private houses, experiencing a completely understandable desire without special costs get an extra residential floor, 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 greatly 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 slight slope, experiences less wind loads than a conventional roof with straight slopes.

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

There are the following types of broken roofs:

Shed. It consists of only one broken slope, while the walls have different heights. Such a roof is the simplest, but it is rare and mainly on extensions.
Gable. Classic variant, which includes two drop-down different sides broken slope. 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 load on the foundation of the 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 of concrete slabs, then to support the racks, they lay on it wooden beam- bed. Racks form the frame of the walls of the attic room, 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
To Mauerlat rafter leg attached with corners and staples. 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 the "cuckoo" weakens the main truss system, in addition, careful sealing of the junction is required different parts roofs. 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.

There are cases when construction companies, in order to expand the attic space, decided to modify the classic truss scheme of a 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 during construction gable roof with straight slopes. But in the case of a sloping roof, a raised puff 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 the field a 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, 8 zones are distinguished in the Russian Federation 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

The actual snow load will depend on the slope of the slope. 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.

The actual snow and wind loads are summed up and, based on the result, the section of the rafters is selected (taking into account their pitch and maximum length). Below is a table for rafters from softwood premium(for other varieties, the values \u200b\u200bwill be different). Its cells indicate the maximum allowable length rafters 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 step of 600 mm should be considered best solution: with such an inter-rafter distance, 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, pine timber is used and edged board no defects or damage

The lumber you will need is:

for floor beams - a bar with a section of 150x100 mm, if the beams are based on external and internal 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.
The Mauerlat is attached to the wall using 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 a 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. In different directions, such a membrane acts differently, so it needs to be laid right 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 with 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 necessary to create a purgeable gap between the waterproofing and 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 a ventilation gap, and the longitudinal rows of the batten 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 a comparative description of the most popular of them.

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 of metal sheets with trapezoidal waves

They make corrugated board from steel sheets, which are covered with 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 and durability, it is the best option for normal conditions, when there is not a large amount of pollution in the atmosphere, 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 the seashore with such corrugated board, or buildings of a chemical enterprise that produces emissions into the environment.

metal tile

Metal tile, as well as corrugated board, is made of steel sheets with polymer coated, only they are given more complex shape, simulating the surface 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 roofing is mainly used on non-residential buildings, agrotechnical structures and buildings located in the southern regions

For fixation plastic panels a frame made of aluminum or steel profiles is attached to the rafters. 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 than the diameter of the 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.

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 wish to acquire attic floor and to successfully prove yourself in the field of a roofer, you need to know how the truss system of a broken roof 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 can be equal, which is why the broken structure will look like a regular gable. 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

Different types of loads will act on each element of the sloping roof truss system. 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. 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 wind strength information determined from the chart is corrected by multiplying by a factor designed for different types 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 the total weight of the roof structure.

Roof mass load

Roof weight - prefabricated characteristic with individual parameters. Basically, it's a lot roofing cake a specific insulated or cold structure with a certain type of coating and a solid or sparse crate specially arranged for the coating. 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. Device 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 approximate average indicators:

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 settlement system warns that "the condition is not met" or is not provided load bearing capacity, the size 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 the typical examples of the construction of an attic with two tiers of layered rafters erected over a brick box. We will attach the rafter system to the Mauerlat - wooden frame from a bar 150 × 200 mm, 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 of the 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 suitable material 50×150mm with a height equal to the corner supports.
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 work will help:

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 construction conditions. However, the examples given by us 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.

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 complex structure like a sloping roof, will require compilation 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 processing of the compositions is carried out on open space, 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 roof structure assumed during the construction of the walls. In the upper row, special studs are laid for the subsequent fastening of the Mauerlat, which is the basis of the roof. This beam is laid around the entire perimeter of the walls, in drilled holes prepared studs are inserted 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 uprights. They are attached to the Mauerlat with metal corners. Strict observance of the horizontal level is required 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 the upper trim. 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. Bottom 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 are the same size, so they are sawn in the same 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 with a 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. Poor ventilation will result in condensation and dampness. Roofing it is worth choosing 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