Do-it-yourself shed roof: device, truss system + photo report of construction, video

If you want to build an extraordinary, unlike the neighbor’s house, take a closer look at the houses under a pitched roof. It gives the building originality. In addition, a shed roof is the easiest to construct. So simple that it is quite possible to do it yourself. 

Advantages and disadvantages

Shed roofs are considered the most inexpensive and easy to install. And this is true, especially with a small width of the building. However, in our country, houses with shed roofs are very rare. For the most part, this is due to the fact that two or four pitched roofs are more familiar to us – they look more familiar. The second challenge is to find a project adapted to our weather conditions. There are a lot of projects on Western resources, but they are designed for a milder climate, as a rule, they have a large glass area. Finding an architect who will competently change the project you like is very difficult. But if you still succeed, and at the same time the harmony of the building is not disturbed, the house turns out to be very original.

Many are afraid of uneven ceilings in some part of the building. Of course, they are more difficult to beat than the standard ones, but the result is of a completely different level – 100% original. True, this time it is very difficult to find a designer who can design such an interior in the vastness of our Motherland, however, it is possible.

There is another way out – to level the ceilings by overlapping, and use the free space under the roof as technical rooms. Implemented and such options and the owners are very satisfied. Yes, the technical rooms are on the ground floor, but upstairs, but there are no problems with groundwater.

These are, perhaps, all the disadvantages or pitfalls that a shed roof can bring. There is, however, one more point that can hardly be called a disadvantage. Due to the peculiarity of the structure, the roofing material on such houses is not visible from the ground. If the terrain is flat, without large elevation changes, there is no point in bothering with the appearance of the roof. It is better to choose simple-looking, but high-quality materials, quiet (the plane is large, it makes a lot of noise in the rain) and reliable. One of the popular options is seam roofing. It provides the proper degree of tightness, not very noisy. Another option is a soft welded roof made of modern materials. Such roofs are even quieter, and modern materials can be used for 20-30 years without repair.

Shed roof device

Organize the required slope of the shed roof due to the difference in heights of opposite walls. One wall of the building is much higher than the other. This leads to an increased consumption of materials for the walls, but the rafter system is very simple, especially for buildings of small width.

With sufficient bearing capacity of the walls, the truss system of a pitched roof rests on a Mauerlat attached to the wall. To make the load distribution more uniform, the upper row of masonry walls is reinforced with longitudinal reinforcement (for brick walls, concrete blocks) or an armored belt is poured over the last row (for walls made of lightweight concrete, limestone, shell rock). In the case of a wooden or frame structure, the role of the Mauerlat is usually performed by the last crown or upper harness.

With insufficient strength of the building material of the walls, most of the load can be transferred to the ceiling. To do this, install racks (step – about 1 meter), on which runs are laid – long bars running along the building. Then the rafter legs rest on them.

When pouring the armored belt or laying the last row, studs are installed in it, with a step of 80-100 cm, with the help of which the Mauerlat is then attached to the walls of the building. In wooden houses, if you do not make an armored belt, it is impossible to lay studs. In this case, installation on pins with a hexagonal head is allowed. Under the pin, a hole is drilled through the Mauerlat, a couple of millimeters smaller than the diameter of the pin. A metal rod is hammered into it, which attracts a wooden beam to the wall. The connection is tightened with a hex wrench of the required size.

Shed roof truss system

Such roofs are especially popular in the construction of courtyard buildings – sheds, garages. It’s just that the dimensions of the buildings allow the use of not very powerful beams, and the beams are required in a small amount. With a building width of up to 6 meters, the shed roof truss system contains almost no additional reinforcing elements (props and girders), which is beneficial. Also attracted by the absence of complex knots.

For Central Russia, for a span of up to 5,5 meters, beams of 50-150 mm are taken, up to 4 meters, 50-100 mm is enough, although in a good way, you need to consider the snow and wind load specifically in your region, and, based on this, be determined with beam parameters.

With a distance between the walls of up to 4,5 meters, a shed roof consists of two Mauerlat bars fixed on the walls and rafter legs that rest on the Mauerlat. A very simple design indeed.

With a span width of 4,5 meters to 6 meters, another bed is required, fixed on a higher wall at the level of the ceiling and a rafter leg, which rests against the beam almost in the middle. The slope angle of this beam depends on the distance between the walls and the level of installation of the bed.

More complex truss systems in a shed roof with a building width of more than 6 meters. In this case, it is optimal if the house is designed in such a way that there is also a load-bearing wall inside, on which the racks rest. With a house width of up to 12 meters, the trusses are still simple, and the cost of roofing is minimal.

For buildings with a width of more than 12 meters, the system becomes more complicated – there are more rafter legs. In addition, the manufacture of beams longer than 6 meters is expensive. If an increase is required only by the width of the roof overhangs, the beams are grown along the edges with fillies. These are pieces of beams of the same section, connected to the beam and fixed on the sides with two wooden plates at least 60 cm long, fastened with bolts or nails, allow the use of mounting plates.

If the total length of the beam is more than 8 meters, they are usually spliced. The joints are additionally reinforced by nailing boards or mounting plates.

There may still be questions about how to attach the rafters of shed roofs to the Mauerlat. There are no fundamental differences. Everyone also makes a cutout in the rafter leg, with which the timber rests against the Mauerlat. In order not to suffer with each rafter leg, aligning its fit, sawing the first one, make a template from a piece of board, thick plywood or timber, exactly repeating the resulting “drank”. All subsequent rafters are cut down before installation. A template is applied to them in the right place, a notch of the required shape and size is circled and cut out.

This was about the rigid fastening of the rafter legs to the Mauerlat. It is used on all buildings that have low shrinkage. On wooden houses, this method of fastening cannot be used – the house settles all the time or rises slightly, which may cause a skew. If the roof is fixed rigidly, it may tear. Therefore, when constructing a shed or any other roof on wooden houses, a sliding connection of rafters and Mauerlat is used. For this there are so-called “sliders”. These are plates, a state of corners that are attached to the Mauerlat and metal strips movably connected to them, which are attached to the rafter leg. There are two such slippers on each rafter.

The choice of the angle of the roof

The angle of the roof slope is determined by a combination of indicators – wind and snow loads and the type of roofing material. First, they are determined with an angle according to climatic conditions (depending on the amount of precipitation and wind loads). After looking at the minimum recommended slope for the selected type of roofing material (in the table below).

If the desired angle is larger, everything is fine, if it is smaller (which happens very rarely), increase it to the recommended one. Making a roof with an angle less than the minimum angle recommended by the roofing manufacturer is not worth it for sure – it will flow at the joints. To make it easier to navigate, let’s say that for Central Russia the recommended slope of a shed roof is 20 °. But it is desirable to count the figure for each region, and even for a different location of the building on the site.

By the way, keep in mind that different manufacturers of the same type of roofing material may require a different minimum slope. For example, the laying of metal tiles of one brand can be done on roofs with a minimum slope of 14 °, the other – at 16 °. And this despite the fact that GOST defines a minimum slope of 6 °.

It is also worth remembering that with a slope of up to 12 °, in order to ensure the tightness of any roofing material, it is necessary to coat all the joints of the material with a liquid waterproofing composition (usually bituminous mastic, less often roofing sealant).

Determine the height to which you want to raise the wall

To ensure the found angle of slope of a shed roof, it is necessary to raise one of the walls higher. How much higher we learn, remembering the formulas for calculating a right triangle. From them we find the length of the rafter legs.

When calculating, do not forget that the length is obtained without taking into account overhangs, and they are needed to protect the walls of the house from precipitation. The minimum overhang is 20 cm. But with such a small protrusion outside the building, the shed roof looks sparse. Therefore, overhangs of at least 60 cm are usually made on one-story buildings. On two-story buildings, they can be up to 120 cm. In this case, the width of the overhang is determined based on aesthetic considerations – the roof should look harmonious.

The easiest way to determine how much you need to extend the roof is in design programs that allow you to draw a building on a scale and “play around” with overhangs. Everything should be displayed in 3 dimensions (the most popular program is ScratchUp). Twist different sizes of overhangs in it, decide which one looks better (this is if there is no project), and then order / make rafters.

Photo report from the construction site: shed roof on a house made of aerated concrete

A house was built in St. Petersburg. There was no project, there was a general idea, which is presented in the photo. The house is made of aerated concrete, the finishing is plaster, the roof is folded, chosen based on low cost, reliability, ease of installation.

After the walls were driven out, an armored belt was poured into them, in which studs (Ø 10 mm) were installed every meter. When the concrete in the armored belt reached the required depravity, a layer of waterproofing (Gidroizol, cut lengthwise into strips of the required width) was laid on the bituminous mastic. A Mauerlat is laid on top of the waterproofing – a beam of 150-150 mm. All lumber used for roofing is dry, treated with protective impregnations, flame retardants.

It is first put in place (it lies on studs, held by assistants), they pass along, knocking with a hammer on the places where the studs are. The places where the studs stick out are imprinted in the beam. Now drill holes and just put it on the studs.

Since the span is large, supports made of timber (150-150 mm) were installed, on which a run was laid that will support the rafter legs.

The width of the roof is 12 meters. This is taking into account the removal of 1,2 meters from the front side. Therefore, the Mauerlat bars and the run “stick out” beyond the walls for just such a distance.

At first there were doubts about such a large offset – the rightmost beam hangs 2,2 meters. If this offset is reduced, it will be bad for the walls, and the appearance will deteriorate. Therefore, it was decided to leave everything as it is.

The rafters are laid from two spliced ​​boards 200 * 50 mm, with a step of 580 mm. Boards are knocked down with nails, in a checkerboard pattern (top-bottom), with a step of 200-250 mm. Nail heads on the right, then on the left, in pairs Two on the top / bottom on the right, two on the top / bottom on the left, etc.). We spread the splicing points of the boards by less than 60 cm. The resulting beam is much more reliable than a similar solid beam.

Further, the shed roof pie for this case is as follows (from the side of the attic – to the street): vapor barrier, stone wool 200 mm, ventilation gap (batten, counter-batten), moisture insulation, roofing material. In this case, it is a dark gray pural.

We will carry out insulation from the inside later, but for now, we are laying a hydro-wind-protective membrane “Tyvek Solid” (vapor-permeable) on top of the rafters.

The membrane is laid from the bottom up, fastened with staples from a stapler. The canvas that rolls out higher goes onto the one already laid by 15-20 cm. The joint is glued with a double-sided tape (bought together with the membrane). Then, strips are stuffed over the membrane, on them – a crate for a folded roof.

First, a crate was made from a board 25 * 150 mm in increments of 150 mm. After laying, walking along the roof, it was decided to strengthen the crate. To do this, between the already laid boards we fill the boards with a width of 100 mm. Now there is a gap of 25 mm between the boards.

Further, on the lower pediment, hooks were stuffed for mounting the drainage system. They are packed unevenly, because due to the large length of the pediment, it was decided to make two receiving funnels at a distance of 2,8 meters from the edge. To ensure flow in two directions, such a relief was made.

Next, you need to bring in pieces of metal (paintings) 12 meters long. They are not heavy, but you can’t bend them, because the “sled” disappears. For lifting, a temporary “bridge” was built connecting the ground and the roof. Sheets were lifted along it.

Next comes roofing work, which differs depending on the type of roofing material. In this case, it was necessary to solve the problem of thermal expansion of the material – galvanized steel (pural) significantly changes its dimensions when heated / cooled. To ensure freedom of expansion, it was decided to fasten the material to the crate behind the seam with movable clamps with a freedom of movement of 15-20 mm.

After laying the roofing material, the filing of the overhangs remains, and they are no different.

Well, in the photo below is what happened after finishing. Very modern, stylish and unusual.

Projects and photos of houses with a pitched roof

As already mentioned, it is difficult to find interesting projects for residential buildings with a pitched roof. So far, these buildings are not popular with us. Perhaps just because of its eccentricity. This section contains several projects or photos of already built houses. Maybe someone will be useful at least as an idea.