Roofing material based on modified bitumen refers to a soft roof. If you chose it for the roof of your house, then it is time to find out what a crate is under a soft roof. The article will become a guide to questions about the types of crates for roofing felt, soft tile, flooring in rolls, and features of its installation. You will receive answers to basic questions about what thickness to choose consumables, what is the step of cracking.
The main problem of a soft roof lies in the name: it is flexible, may sag if the attachment points are far apart, the service life depends on the quality of the base.
The material is selected so that it meets the requirements for the crate:
strength sufficient to withstand all types of mechanical loads (on the weight of the roofing material , snow, wind effects);
no knots, cracks, grooves and any other defects in lumber exceeding 0.6 cm;
elements geometrically regular , straight, without sagging;
possibility of mounting in such a way that fasteners (nails, screws, brackets) did not speak d the surface of
life comparable to the warranty period of roofing material.
The following materials meet the demands put forward:
Edged or grooved boards at least 14 cm high quality. The functionality of the batten depends largely on the moisture content of the board: wet lumber begins to dry out and jarred, which will lead to a violation of the integrity of the roof, the appearance of bulges, tears;
Bars of wood dried to a moisture content of not more than 20%. The size of the bars is matched to the crate step;
Plywood is durable, environmentally friendly, easy to handle, with a sufficient level of wear resistance, smooth and ductile. The small weight of sheets will allow to establish a roof on different types of the base. Plywood under a soft roof is taken only moisture resistant, which is indicated by the manufacturer when marking. The advantage is the budget price of sheets;
OSB plates are dense, durable, moisture resistant, resistant to deforming loads. From OSB will get a flat surface under the roof, without height differences.
When choosing a material with wood in the base, pay attention to the presence of impregnation with antiseptics, fire retardants.
Most often, sheathing is divided into variations in two basic ways of installation:
Sparse frame . Parts of the structure are placed on the rafters with a certain step, there will be a gap between them. Without additional coverage, the soft roof will sag, deform. The solid roof is laid directly on the thinned crate.
Solid flooring . The building material is laid end-to-end, with a distance of at least 2 mm to prevent puffing, jumps in height. On this basis, simply place the vapor and moisture insulation, insulation. Used for mounting the roof under a soft roof.
Depending on the purpose of the building, the climatic conditions of the area where it is located, the sheets for a continuous batten are laid either directly on the rafters (single-layer flooring), or on a rarefied frame (double flooring).
Flooring in one layer is used for buildings that do not require insulation, more often for economic purposes. He performs fast.
The double coating has special advantages:
over stable , durable;
a ventilation gap is formed between the rarefied frame and the solid part;
a heat-insulating material is placed between the rafters and the rails of the rarefied lath.
The disadvantages include the additional weight of the frame elements, which must be considered when choosing the type of foundation.
The board is cut or grooved. Its width depends on the distance between the lines.
Sling pitch, mm
Board thickness, mm
The order of execution of work on the finished truss system:
boards are cut off in size;
installation starts from the bottom;
fasten elements perpendicular to rafters and on them, with orientation along the ridge;
protruding fasteners are carefully sunk into wood;
board joints must fall on the attachment points to the rafters.
The wood is subject to deformation when the temperature and humidity conditions of the external environment change. To the flooring of the boards is not distorted from temperature fluctuations, between the elements leave a gap of up to 3 mm.
On our website you can find contacts of construction companies that offer services roof design and repair . Directly to communicate with representatives, you can visit the exhibition of houses "Low-rise Country".
Sheets of plywood, OSB boards are cut to the size of the roof. Their thickness is taken from 9 mm. Any shield material is attached to the crate in a staggered manner, so that the connecting seams of adjacent rows do not intersect.
The deflection resistance of sheets is directly related to their thickness. Thinner shields should have more fastening lines, and therefore the step of rafters is minimal. OSB thickness for roofing is indicated in the table:
Step of slings, mm
Plate thickness, mm
Pitch of fastening the sheet of shield material to the rafters 15 cm sheet connecting lines, 10 cm along the edges, 30 cm along individual lines. A gap of 2 to 3 mm is created between the sheets.
The first layer is formed from a board with a thickness of 25 mm, whose width varies from 10 cm to 14 cm. A material for a thin layer can be a timber.
The second layer is laid out of boards 2-2.5 cm thick, 5-7 cm wide.
Work execution order:
Bars attached to the rafters parallel to the ridge. The pitch of the batten under the soft roof of the first layer is 20-30 cm;
the second layer is placed on top - diagonally, starting from the ridge. There is a gap between the boards.
Double sheathing, which uses shield materials the most practical and functional option. It will provide a reliable base for all types of soft roof, but usually it is used under soft tile.
For the qualitative arrangement of this type of double sheathing, the following materials are used:
Steam insulation membrane . It performs a protective function of the "greenhouse" effect created by the internal heat of the building.
Heat insulation . The most budget and common option is mineral wool. Thickness is selected depending on climatic conditions, general requirements for roof insulation. The width of the pieces of insulation should not be less / more step rafters.
Bars / boards for the first sparse layer of size 5x5.
The vapor diffusion membrane protects the insulating layers of the roof from moisture, dust, and destruction.
Plywood , OSB boards.
It might be interesting! In the article on the following link, read about how the roof is made of corrugated .
Roof construction under soft tile consists of several stages:
Strengthening the vapor barrier to the rafters from the inside of the roof. Laying is done by strips overlapping each other and on the walls.
Coating of vapor barrier with insulation . Depending on the required level of insulation, one or several layers are laid. The seams of the second and subsequent layers are staggered relative to the first, each other. That the heater did not slide, it is fixed with the supporting boards nailed from the attic.
If necessary, a crate of bars is packed on the first layer of insulation .The resulting cells are filled with insulation with a thickness equal to the height of the beam.
Coverage with a vapor diffusion membrane . Strips of material stacked overlap in 10 cm at each other, fastened with a stapler. The tightness of the joints can be enhanced with a special adhesive tape, sealant.
With the help of planks / bars a sparse crate is made, which is also necessary to create a ventilation duct. The fastening pitch is 30 cm.
The panel cover is superimposed on top. Determining what thickness of OSB on the roof under a soft roof to take depends on the pitch of the first batten. But it should not be less than 9 mm. Fasten sheets vrazbezhku with gaps up to 10 mm.
The entire multi-layer system is reinforced with curtain strips.
The thickness of the material for the batten should be sufficient to withstand without critical deformation, weight of roofing material, mass of precipitation. In this case, the weight of the lathing itself should not significantly increase the foundation load. The parameters of consumables also depend on the design of the truss system.
This means that at the design stage it is necessary to take into account the parameters not only of soft tile, but also of the batten.
From the video you can find out how to properly make a roof lath
It might be interesting! In the article follow the link read about the project of a house with a wavy roof .
Competent installation of the batten under a soft roof requires not only theoretical knowledge, but also some practical skills. To perform this work, the best option would be to turn to professionals who will do the work with high quality and with a guarantee.
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