What is sheathing for a soft roof? Lathing for a soft roof - design requirements What is the pitch of lathing for a soft roof

The category of materials referred to as soft roofing includes several commonly used coatings. These include roofing felt, soft bitumen shingles, and several types of fused rolled materials. They all differ from each other in appearance and characteristics, but their production is based on one component - modified bitumen. It is this that gives roofing coverings that very flexibility and softness. The material itself does not have a rigid shape, so a strong and rigid sheathing is needed under it, which will withstand external loads. In this case, the soft roof will only provide protective and decorative properties.

Types of sheathing for soft roofing

If we talk about the sheathing in general, then it comes in two types: sparse and solid. The first is assembled from boards or bars, between which gaps are left or, as they are also called, installation steps. The second is a continuous flooring without gaps. For soft roofing, it is the second option that is used, because when laid on a loose sheathing, soft roofing materials will sag between its elements.

Under soft roof make a continuous sheathing, otherwise the material will sag in the cracks between the boards

Sheets are used as flooring for continuous sheathing moisture resistant plywood, OSB boards and boards. The latter should be either edged or tongue-and-groove from softwood. As for moisture-resistant plywood, it must be chosen correctly by brand, because there are two positions on the market with this name:

FC, which is recommended for use only for finishing interior spaces.
FSF, which is used for both internal and external installation.

For continuous sheathing, FSF is suitable. This material is made from several layers of veneer (from 3 to 21), which are glued together special composition based on phenol-formaldehyde resins. It should be added that in the production process of FSF plywood, each layer is first treated with bakelite varnish, so the material has high strength and water resistance.

As for OSB, for the lathing you also need to choose a waterproof modification, i.e. grades OSB-3 and OSB-4. The latter is intended for structures that are subjected to maximum loads at high humidity air, so it is quite expensive. For roofs, you can use OSB-3 plywood, which is not inferior in moisture resistance to the fourth model.

When assembling the flooring, you can leave a small gap between the elements, the size of which should not exceed 1 cm. It is called compensation because it will compensate for the expansion wooden products due to changes in humidity and temperature.

Types of continuous sheathing

The sheathing for a soft roof can be single or double. In the first case, boards or panels are laid directly along the rafters. In the second, a sparse sheathing is first installed, and a solid one is installed on top of it. The second option is preferable because there is space between the two layers, which is used for ventilation of the roof. And this makes it possible to remove moist air vapors that rise from the interior of the house. It is they that on uninsulated roofs cause the formation of ice and condensation on the rafter system.

But this is not the only criterion for choosing double flooring. Much will depend on the angle of the roof slopes.

When the slope is inclined 5–10°, a single-layer flooring can be used.
In the range from 10 to 15°, a double sheathing is laid with a step between the lower elements of 45–50 cm. For the lower sheathing, it is better to use bars with a section of 50x50 mm.
If the slope angle exceeds 15°, then the installation step can be increased to 60 cm.

In principle, you can increase the pitch of the bottom sheathing up to 100 cm, depending on the size of the lumber used for it. For example, if a board 40 mm thick and 120 mm wide was used for this. The smaller the cross-section, the smaller the pitch, and vice versa. For each material, its own step is selected relative to its thickness.

Table: ratio of the spacing of the sparse sheathing to the thickness of the solid flooring elements

How to calculate the amount of material for lathing under a soft roof

Taking into account the above-mentioned relationships between the spacing of the sheathing elements and their thickness, it is possible to make quite exact calculation this design. To do this, you will have to first take the dimensions of the roof itself, which are indicated in the building drawing. And if the roof is a complex multi-level and multi-slope structure, then it needs to be divided into simple geometric figures. It is on their basis that the total roof area is calculated.

In this case, you will have to take into account the angle of inclination of each slope, because the smaller the angle, the greater the loads the sheathing system is subjected to. This means that you will either have to reduce the spacing of the boards or bars, or increase the thickness of the slab and sheet flooring. Therefore, to simplify calculations when determining total area roofs apply correction factors. For example, when the slope is inclined at 35°, a multiplying factor of 1.221 is used.

Calculation of a solid structure

With the calculation of a continuous sheathing, the situation is simpler, because it covers the entire area of the slopes. That is, its area will be equal to the area of the roof. Let's look at an example of calculating the number of plywood sheets for a slope with an area of 50 m².

In the construction business, when calculating the amount of building materials, a small reserve is made in the range of 5–10%. Here we need to do the same, so the final result is 23–24 sheets.

The number of OSB boards is calculated in exactly the same way. But with boards it’s a little more complicated. First of all, you need to calculate the area of one selected board. The length of edged boards varies from 1 to 6.5 m in increments of 0.25 m. Width ranges from 75–275 mm in increments of 25 mm.

Let’s say a board 3 m long and 0.1 m wide is used for the sheathing:

We calculate the area of one board: 3∙0.1=0.3 m².
A slope with an area of 50 m² will require 50:0.3 = 166.66 boards.
Round to the nearest whole number and add a margin of 10%: 167∙1.1 = 184 boards.

Calculation of sparse sheathing

For this calculation, the area of the slope itself is not required. The length of the roof and its height are required, that is, the distance from the overhang to the ridge.

Rules for installing sheathing under a soft roof

Regardless of whether one- or two-layer sheathing is used on the roof, the main requirement for the structure is a smooth and durable surface without defects and flaws in lumber. That is why when using boards, calibrated material is selected.

According to construction canons, the rafter system is aligned along the slopes in one plane, so you need to be sure that the ends of the rafter legs are already aligned. This means that we can assume that the boards, plywood or OSB boards being laid will lie in the same plane.

The sheathing elements must be joined along the rafters. A board protruding beyond the rafters will not provide strength during installation roofing material

You need to start installation from the cornice, or more precisely, from the lower ends of the stops. The boards are selected in length so that two adjacent elements are joined on one rafter beam. If this fails, you will have to trim them, which will increase the amount of waste. The same goes for sheets and slabs.

The boards are laid with a small gap of 1 cm and attached to the rafters with nails or self-tapping screws. Fastening is best done with end side. If screws or nails are installed according to front side, then their caps must be driven into the body of the lumber to a depth of 0.5 mm. In this case, on each rafter, two fasteners must be nailed to the board - one on each edge.

Plywood sheets or OSB boards on the roof as a continuous sheathing should be laid staggered with an offset of a third or half of the panel

Concerning flat materials for sheathing, they are placed offset relative to each other by a third or half a sheet. This is done so that the loads acting on the continuous sheathing are evenly distributed over its entire surface. In this way, the panels are laid perpendicular to the rafters. Plywood with dimensions of 1.5x2.5 m can be installed along the rafters. At the same time, it will be necessary to take into account that sheet material cannot bear large loads, so at least three must fall under it rafter legs: one exactly in the middle and two at the edges. But here, too, you will have to take into account that two adjacent plywood sheets must be joined on one rafter. A gap between them (3–5 mm) is mandatory.

Plywood and OSB are fastened with galvanized self-tapping screws or ruff nails around the perimeter every 10–15 cm and along the entire plane along the rafters in a checkerboard pattern. It is these fasteners that need to be used, because they can withstand the stresses that arise in OSB boards or plywood sheets due to changes in humidity and temperature.

The procedure for laying flat panels on a discharged sheathing:

A string is stretched along the edges of the rafters, defining the boundary of the roof overhang. It is tied to two self-tapping screws, which are screwed into the two outer rafters located on different edges of the roof.
The first sheet is laid along the outer edge of the first rafter leg, while its adjacent edge must accurately follow the twine.
The first sheet of continuous sheathing is laid strictly along the edge of the rafter leg
The first sheet is fastened with self-tapping screws 50 mm long along the rafters in increments of 20–30 cm.
The bottom row is assembled in this way.
The bottom row is laid with the panels joining on the rafters
The next row starts with half a sheet, so one panel must be cut in half.
The half is attached to the rafters, like the whole sheets, with the same screws with the same pitch.
The second row of continuous sheathing begins with half of the slab, so that the following elements are attached at intervals from the first row
Then whole sheets are used.
The third row begins to be assembled from a single slab.

Video: how to properly lay boards as sheathing elements

Continuous sheathing over open sheathing

In principle, there are no serious differences from the installation technology described above. Simply a solid structure is laid on boards, which are placed on the rafters with a certain distance between the rows. No boards are used to create a continuous flooring. Plywood or OSB is being installed. At the same time, all the above-described requirements are preserved both in terms of the installation scheme of the panels and in the method of their fastening.

Counter-lattice for soft roofing

To insulate the roof, it is necessary to lay thermal insulation material between the rafters. From the outside attic space it closes vapor barrier membrane, and from the side of the sheathing - waterproofing film. You cannot immediately lay the sheathing and make flooring from OSB boards or plywood sheets. It is necessary to create a ventilation duct that will remove moist air vapor from under the roof space. Therefore, bars with a cross section of 50x50 mm are laid along the rafters. This is the counter-lattice, and the space between the waterproofing and the solid flooring is the ventilation gap.

The process of assembling an insulated roof structure consists of the following steps.

From inside the future attic, insulation is laid between the rafters. The main requirement for installation is tight pressing thermal insulation material to the planes of the rafter legs so that cold bridges do not form.
The insulation is placed in the space between the rafter joists so that there are not even minimal gaps left
Placed on top of the insulation vapor barrier film, which is attached to the rafters with metal staples using a stapler. The film is laid in rows with an overlap of 10–12 cm. The joint must be covered with self-adhesive tape.
The vapor barrier film is laid with an overlap and secured with staples
Next, the work is transferred to the external part rafter system, where a waterproofing membrane is laid on top of the legs in the same way as a vapor barrier below. Laying should begin from the bottom of the cornice.
Counter-lattice elements are installed and fastened along the rafters, for which wood screws 70 mm long are used. The fastening pitch is 40–60 cm.
To create a ventilation gap, bars are attached along the rafters, onto which horizontal sheathing is laid.
Lathing elements - boards - are installed across the counter-lattice. They are attached with self-tapping screws 50 cm long.
Plywood sheets or OSB boards are installed and fastened on top of the sheathing in a checkerboard pattern. The fastening pitch is 20–30 cm.

Typically, this design is used if there is no sparse sheathing on the roof, or it is assembled from boards 20–25 mm thick. Such a gap will not be sufficient to effectively remove moist air.

Video: rules for laying continuous sheathing on the roof

Continuous sheathing under soft roofing material is the only way to guarantee the quality of the final result. Minimum gaps will not reduce it, but fulfilling the basic requirement - the formation of a flat and durable surface - will create conditions under which the soft roof will last its warranty period.

Soft roofing in last years has gained popularity among developers. But not everyone knows in advance that the base on which bitumen shingles are usually laid is very different from the sheathing on which slate, ondulin or metal tiles are mounted. Let's try to figure out how the sheathing for a soft roof should be arranged and how its installation differs from the installation of a regular sheathing.

The mauerlat on which the entire rafter system rests serves as a kind of foundation for the roof. Flexible tiles do not tolerate unevenness, unnecessary bends, height differences and protruding nails in the base on which it will be laid, so it is necessary to take very seriously geometric parameters roof structures from the very beginning. All mauerlat bars must lie strictly horizontally for any structure configuration. And the lines connecting the ends of the mauerlats at the ends of the buildings should make an angle of 90° with them. If a device is also provided at the ends pitched roof, then the end Mauerlat should lie perpendicular to the longitudinal ones in the same horizontal plane with them.

Rafters - the frame of the future roof

If the Mauerlat is laid and secured correctly, then installation of rafters prepared according to one template, even for figured roofs, will be simple. As a matter of fact, this is where the similarity with frames for other roofing materials ends. Under rigid roofing sheets, the sheathing can be made from Not edged boards in one layer with an interval between boards of 150–400 mm. Under flexible tiles it is necessary to prepare a continuous, even and smooth base in two layers:

The actual sheathing is made of calibrated (one thickness) edged boards with a width of 100 mm, which can be mounted at intervals from 100 to 400 mm.

A solid base on which soft tiles are glued, made of plywood or OSB-3 board (osb, OSB-3)

Plywood and/or OSB-3 board must be moisture resistant! All wooden structures roofs: mauerlat, rafters, ridge run, racks, struts, boards and timber for sheathing, must have a humidity of no more than 20%.

When calculating the distance between the rafter legs, it is necessary to take into account the thickness of the board, plywood sheets or OSB boards. If the pitch is 500 mm, then the thickness of the board can be 20 mm, and plywood or OSB boards can be 10 mm. With a step of 1000 mm, the thickness of the board should be 25 mm, and plywood or OSB board should be 20 mm thick. The distance may be different, and accordingly, the thickness of the boards and sheets of plywood, or OSB-3 boards should also be different. Here you need to understand that the board serves as a sheathing to support the slab or plywood. If the distance between the boards is too large, the sheet material may bend over time and sag between the supports, which will lead to deformation of the soft roof. The figures for the width of the board and the thickness of the materials used are minimal. Therefore, if you have the funds, you can purchase plywood or a board of a thickness greater than that required by calculations. In this case, the pitch of the board can be slightly increased. If the thickness is less than required, it would be better to make the sheathing of boards continuous. What is the reason for this? The thing is mechanical characteristics materials:

The board can maintain its rigidity for decades when the right conditions operation and will lie flat even with a rafter pitch of 1200 mm or more. Of course, the board must have a thickness corresponding to this step.
Over the years, plywood and OSB-3 boards can sag under the influence of temperature changes and variable humidity if they rest on points or support lines with a distance of even 500 mm between them.
For all its rigidity, a board can “lead” over time, warp, the edges of individual boards can come out of common plane surfaces. But flexible tiles don’t like this. It will break, be pressed, or rub through, which will necessitate roof repairs.
Obviously, using only boards or only plywood or OSB boards will lead to the fact that very soon the bitumen shingles will begin to tear at the seams of the boards or sag along with the boards or plywood. This may mean that the roof installation will have to be done again.
Only the combination of the rigidity of the board and the flat surface of OSB boards or plywood will give reliability to the base for soft tiles, and there will be no need for roof repairs for a long time.

To find the best option, you need to find out the cost of all materials and calculate the consumption when different options step. For example, the cost of an OSB-3 board with a thickness of 20 mm is almost twice as high as the cost of this board with a thickness of 10 mm. Preparation truss structures roofs for installation must take into account the fact that wood is a flammable material and susceptible to rotting. Therefore, it is recommended to carry out appropriate treatment with fire retardant impregnations and antiseptics, and in places where the rafter legs come into contact with the wall, it is better to lay waterproofing material. For example - roofing felt. A layer of waterproofing must be placed under the Mauerlat.

Sheathing device

The sheathing for a soft roof must meet the following requirements:

Solid flat smooth surface bases without deflections, potholes, chips, cracks and protruding chips or nails.
Technical gaps between OSB slabs or sheets of plywood necessary to compensate for their possible expansion should not exceed 6 mm.
During installation, the edges of sheets and slabs must be cleaned so that they are not sharp, even if they lie close to each other.

Only if these conditions are met will flexible tiles serve long and reliably. One more an important condition is the possibility of ventilation of the under-roof space. If the attic is non-residential, then under the eaves there should be a gap for air to enter under the roof, and under the ridge there should be “windows” for air to escape outside. When installing an attic interior lining The walls and ceiling will need to be designed so that air can circulate freely in the space between the roofing “pie” and the cladding of the room from bottom to top. This space, by the way, will serve as additional sound and thermal insulation for the attic. Alternatively, when initially planning an attic with additional insulation, the best option There will be a waterproofing device under the roof. To do this, you need to pull it along the rafters waterproofing membrane, secure it with a counter-lattice made of timber with a cross-section of 50 x 30 or 50 x 50 mm and install two layers of base for the soft roof along the counter-lattice. The gap between the membrane and the sheathing of boards will serve as a ventilation duct for air circulation. In this case, you must remember to leave vents in the upper part of the roof so that the air coming from under the eaves and rising up under the roof has the opportunity to escape. Installing a two-layer base under flexible tiles leads to an increase in the cost of the roof per 1 m², but at the same time allows you to save on insulation. The finishing touch of the base device under soft tiles should be a montage cornice strip or drip.

They will serve as protection against water entering the wooden structures of the rafter system. If you plan to install gutters, then they need to be installed before the drip line.

Soft roofing is not just one roofing element. The concept includes a group of special roofing materials, which, as the name implies, have a soft structure. This includes bitumen and soft tiles, roofing felt, guided roll coverings etc. Although they may all look different in appearance, they are made on the same basis - from modified bitumen. He is the one who does finished products soft and flexible. Based on this, it is logical to replace the feature of such a roof: the products cannot maintain a rigid shape on their own, without auxiliary elements. The same applies to withstanding loads. In order for the roof to fully perform its functions, it is important to properly make the foundation for it.

The frame must be rigid and durable. It is the sheathing under the soft roof that creates such conditions. But, it is different from the usual base. How? What is its feature and how to do it quality foundation? Let's find out.

What is it like, roof sheathing

In general, there are two types of bases for roofing materials:

Sparse base.
Solid base.

What's the difference between them? A sparse base is a structure made of boards that are placed on the rafters. At the same time, when arranging such a sheathing, it is important to maintain the step (distance) from one plank to another. On average, it is 20-55 cm. It all depends on the type of roof, waves, etc. But, such a base is only suitable for hard surfaces. They do not sag and stay level on the roof. The photo shows what this sheathing looks like.

But the sheathing for a soft roof needs to be made solid, since with a conventional base it will hang down. It's all about flexible structure. The base can be a solid flooring made of boards, OSB boards and moisture-resistant plywood. There is no sheathing pitch for a soft roof, but between the slats you can make a small ventilation gap, the width of which does not exceed 1 cm.

Only such a base is suitable for this type of roof.

Note! Since the layer turns out to be continuous, much more consumables will be required. This, accordingly, makes the installation of a roof much more expensive than a conventional one.

Types of sheathing

If everything is clear with continuous flooring, then it is important to note that the structure can be made not only in one layer. There are two types of continuous sheathing:

We've sorted out the theory. What can I say about practice? How to actually do everything yourself?

How to make a single-layer continuous sheathing

If we compare these two types of lathing, it is much easier and cheaper to make this option. But, it is not that effective. The task is to put the covering on the rafters, without various additional elements. For household structures and budget construction without insulation just right.

Using slats

Timber or tongue and groove boards are suitable for work. It is strictly forbidden to make flooring from unedged materials. The thing is that all the irregularities and defects will be visible on the surface of the soft roof. Therefore, the decorative side immediately rolls to zero. And the insulation from moisture will be of poor quality, which will negatively affect the entire roof.

This is the simplest sheathing, which consists of slats packed across the rafters.

What materials should be used for a soft roof? Here are the requirements for slats:

surface without knots, smooth and even;
width - from 10 to 14 cm, thickness - 2-3.7 cm. It all depends on the rafter pitch. If it is equal to 90 cm, then required thickness 2 cm, exactly 90 cm - thickness 2.3 cm, at 120 cm - 3 cm. And if the pitch of the rafters is 150 cm, the thickness needed is 3.7 mm;
the humidity of the slats is 20% and no more, so that the material does not dry out and the fasteners do not fall out;
It is important to treat the elements with an antiseptic.

The construction of sheathing for a soft roof consists of securing the materials to the rafters. Work must be done from the overhang, moving towards the ridge. The joints of the boards are made on the rafters, and the fasteners are hammered closer to the edge. A ventilation gap is made between the slats.

Using Shields

It is much easier and faster to work with panel materials (plywood, OSB). They are flexible, moisture-resistant and durable. The surface will be perfectly smooth. The photo shows in detail what such a roof looks like and how to make the lathing.

What should the material be:

moisture resistant;
recommended thickness is from 0.9 to 2.7 cm. If the rafter pitch is up to 60 cm - 0.9 cm, the pitch of 60 cm is 1.2 cm, the pitch of 90 cm is 1.8 cm, the pitch of 120 cm is 2 .1 cm, step of 150 cm - 2.7 cm;
everything needs to be treated with an antiseptic.

Double sheathing device

This is a two-tier design. Just like in the first case, there are two options.

From boards

Boards serve as the base and covering. The technology of the device can be seen in the photo.

The slats of the first row should be at least 2.5 cm thick and 10-14 cm wide. The thickness of the top layer boards is 2-2.5 cm and 5-7 cm wide. As usual, lumber should be treated with an antiseptic in advance.

The technology is as follows: parallel to the ridge, a backing of boards is laid in increments of 20-30 cm. A second layer of boards is piled on top of the base, diagonally (45˚). This leaves a gap of 3 mm. The sheathing is installed starting from the bottom, moving upward. The flooring is suitable for roofing felt. The second option is suitable for tiles

From shields

This combined option, consisting of backing boards or bars, and a second top layer of OSB or plywood. For cold roof the technology is as follows:

Boards are nailed perpendicularly to the rafters at the required pitch.
Plywood or OSB is mounted on top.

In this case, there is no waterproofing and insulation. But if you want to make the right roofing pie, then it’s a little more complicated.

A counter-lattice is installed along the rafters. On top of it, perpendicular to the first layer of sheathing made of boards. And now, shields are stuffed on top of the board base. The counter-lattice creates a ventilation gap. At the same time, a layer of waterproofing is attached to the rafters, which is secured with a counter-lattice. The diagram below shows how all the work is done.

Let's sum it up

Soft roof on wooden sheathing can last for many years. It has many advantages, including light weight, noiselessness, long service life and appearance. But in order to bring all this to life, you need to make high-quality sheathing, then the soft roof will only delight you. Although the cost will be slightly higher than for a conventional roof, you will save on hiring workers and can do everything yourself. To make it easier for you to navigate, we suggest you additionally watch a video on how to carry out all the work on installing such a roof. Then the task will seem easy and quick for you.

Roofing materials based on modified bitumen are classified as soft roofing. If you have chosen it for the roof of your house, then it’s time to find out what sheathing for a soft roof is. The article will become a guide to questions about the types of sheathing for roofing felt, soft tiles, flooring in rolls, and the features of its installation. You will receive answers to basic questions about what thickness to choose Consumables What is a sheathing pitch?

Source tiu.ru

What is the sheathing made of?

The main problem with a soft roof lies in the name: it is flexible, can sag if the attachment points are located at a large distance from each other, the service life depends on the quality of the base.

The material is selected so that it meets the requirements for the lathing:

strength sufficient to withstand all types of mechanical loads (from the weight of roofing material, snow, wind);

absence knots, cracks, gouges and any other defects in lumber, the size of which exceeds 0.6 cm;

elements geometrically correct, straight, without sag;

the possibility of installation in such a way that fasteners (nails, screws, brackets) did not protrude above the surface;

life time comparable to warranty period operation of roofing material.

Source svetlyi-dom.ru

The following materials meet the requests:

Edged or tongue-and-groove boards at least 14 cm wide High Quality. The functionality of the sheathing largely depends on the moisture content of the board: wet lumber will begin to dry out and warp, which will lead to a violation of the integrity of the roof, the appearance of bulges and tears;

Wooden bars, dried to a moisture content of no more than 20%. The size of the bars is selected according to the pitch of the sheathing;

Plywood– durable, environmentally friendly, easy to process, with a sufficient level of wear resistance, smooth and plastic. The light weight of the sheets will allow you to install the roof on different types foundation. Only moisture-resistant plywood is used for soft roofing, as indicated by the manufacturer when labeling. The advantage is the budget price of the sheets;

OSB boards dense, durable, moisture-resistant, resistant to deforming loads. OSB will provide a flat surface for the roof, without height differences.

When choosing a material with wood as a base, pay attention to the presence of impregnation with antiseptics and fire retardants.

Types of lathing

Most often, the lathing is divided into varieties according to two main installation methods:

Sparse frame. Parts of the structure are placed on the rafters with a certain spacing; there will be a gap between them. Without additional covering, the soft roof will sag and become deformed. The solid roof is laid directly on the sparse sheathing.

Solid flooring. The building material is laid end-to-end, with a distance of at least 2 mm to prevent swelling and height changes. On this basis it is easy to place vapor and moisture insulation and insulation. Used for installing roofs under soft roofs.

Depending on the purpose of the building and the climatic conditions of the area where it is located, sheets for continuous sheathing are laid either directly on the rafters (single-layer decking) or on a sparse frame (double decking).

Single-layer flooring is used for buildings that do not require insulation, most often for household purposes. He performs quickly.

U double coating there are special advantages:

more sustainable, durable;

between the sparse frame and the solid part is formed ventilation gap;

between the rafters and beams of sparse sheathing is laid thermal insulation material.

The disadvantages include the additional weight of the frame elements, which must be taken into account when choosing the type of foundation.

Source stroim-dom.radiomoon.ru

Arrangement of a single-layer structure made of boards

The board is taken hewn or tongue-and-groove. Its width depends on the distance between the slings.

Work order on a finished rafter system:

boards are circumcised to size;

installation starts from the bottom;

elements are attached perpendicular to the rafters and on them, with orientation along the ridge;

protruding fastening parts carefully embedded in the wood;

board joints should be located at the points of attachment to the rafters.

Wood is subject to deformation when the temperature and humidity conditions of the external environment change. To prevent board flooring from warping due to temperature fluctuations, a gap of up to 3 mm is left between the elements.

Source stroyinvest-market.ru

On our website you can find contacts construction companies who offer services roof design and repair. You can communicate directly with representatives by visiting the “Low-Rise Country” exhibition of houses.

Installation of a single-layer panel structure

plywood sheets, OSB boards cut to fit the size of the roof. Their thickness starts from 9 mm. Any panel material is attached to the sheathing in a checkerboard pattern, so that the joining seams of adjacent rows do not intersect.

Resistance to deflection of sheets is directly related to their thickness. More thin shields must have more fastening lines, which means the rafter spacing is minimal. The thickness of OSB for roofing is indicated in the table:

The step of attaching a sheet of panel material to the rafters along the line of connection of the sheets is 15 cm, along the edges 10 cm, along individual slings - 30 cm. A gap of 2 to 3 mm is created between the sheets.

Source reminform.com

Algorithm for forming a two-layer sheathing from boards

The first layer is formed from a board with a thickness of 25 mm, the width of which varies from 10 cm to 14 cm. The material for the sparse layer can be timber.

The second layer is laid from boards 2-2.5 cm thick and 5-7 cm wide.

Work order:

The bars are attached to the rafters parallel to the ridge. The pitch of the sheathing under the soft roof of the first layer is 20-30 cm;

Stacked on top second layer- diagonally, starting installation from the ridge. A gap is left between the boards.

Two-layer lathing with panel materials

Double lathing, which uses panel materials most practical and functional option. She will provide solid foundation under all types of soft roofing, but usually it is used under soft tiles.

For quality arrangement this kind double battens the following materials are used:

Vapor barrier membrane. She performs protective function from the "greenhouse" effect created internal heat building.

Insulation. The most budget and common option is mineral wool. The thickness is selected depending on climatic conditions, general requirements for roof insulation. The width of the insulation pieces should not be less/more than the pitch of the rafters.

Bars/boards for the first sparse layer of size 5x5.

Vapor diffusion membrane protects the insulating layers of the roof from moisture, dust, and destruction.

Plywood, OSB boards.

Source remontcap.ru

The installation of a roof under soft tiles consists of several stages:

Strengthening the vapor barrier to the rafters With inside roofs. Laying is done in strips overlapping each other and on the walls.

Covering the 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 one, each other. To prevent the insulation from slipping, it is fixed support boards, nailed from the attic side.

If necessary, apply the first layer of insulation the sheathing is filled with bars. The resulting cells are filled with thermal insulation with a thickness equal to the height of the beam.

Vapor diffusion membrane coating. The strips of material are laid with an overlap of 10 cm on each other and secured with a stapler. The tightness of the joints can be strengthened using special tape or sealant.

Using boards/bars a sparse crate is made, which is also necessary to create ventilation duct. The fastening step is 30 cm.

Superimposed on top panel covering. Determining what thickness of OSB to use on the roof under a soft roof depends on the pitch of the first sheathing. But it should not be less than 9 mm. The sheets are fastened staggered with gaps of up to 10 mm.

The entire multi-layer system is reinforced with cornice strips.

Source tehno-mashina.ru

Important points

The thickness of the material for the sheathing must be sufficient to withstand the weight of the roofing material and the mass of precipitation without critical deformation. At the same time, the weight of the sheathing itself should not significantly increase the foundation load. The parameters of consumables also depend on the design of the rafter system.

This means that at the design stage it is necessary to take into account the parameters of not only soft tiles, but also the sheathing.

Video description

From the video you can learn how to properly make a roof sheathing

Conclusion

Proper installation of lathing under a soft roof requires not only knowledge of theory, but also some practical skills. To do this job, the best option will turn to professionals who will do the work efficiently and with a guarantee.

After manufacturers of soft roofs made some kind of revolution, where roofing felt ceased to be a dominant product, the popularity of bituminous materials began to gradually grow. I would like to note that soft coverings diverged in several directions at once and began to strengthen themselves in their niches. Some manufacturers changed the structure of roofing felt, added modifiers, and got completely new roll materials, but others took a completely different route by creating asphalt shingles. Lathing made of lumber for a soft roof is distinguished by its appearance and structure; in this article I will try to tell you as much as possible about it.

Types of lathing

As a rule, rafter systems are created from conventional lumber. There are boards and beams here. Nails or bolts are often used as fasteners; self-tapping screws are less common. In the construction industry, there are only 2 types of lathing:

Discharged. It is created from bars or boards. These elements are attached to the rafter legs across the slope. The protruding parts of the sheathing create gable overhangs on both sides of the building. During the construction process or a little later, the overhangs of the structure can be sheathed with soffits or any other similar materials.
Solid. This lathing is divided into 2 more subtypes: single-layer and two-layer. The first differs from the second only in the absence of additional plywood. This lathing has an ideal structure for laying soft roofs.

Lathing for flooring soft material can be created with some gaps. In some situations, the sheathing step for flexible tiles can reach up to 50 centimeters. After such a system is created, OSB products or moisture-resistant plywood are laid on top of it.

Materials for the manufacture of high-quality lathing

It's no secret that almost all sheathing is made of wood. When purchasing such a product, it is important to pay attention to small details.

When purchasing wood, it must be smooth and even, not have any knots, cracks, chips or the like.
It is dangerous to purchase lumber with a moisture content of more than 20%, since during the drying process they may begin to warp. The same applies to installation, there is no need to rush, it is better to let the wood dry to its optimum level.

To prevent rotting and increasing the degree of fire of lumber, they must be treated with protective solutions. In the first case, antiseptics will help you, and in the second, fire retardants. There are universal mixtures on sale that relieve wood from several problems at once and improve its overall quality.
The sheathing for soft tiles is usually created from moisture-resistant plywood or OSB products.
After laying all the lumber in place, it is advisable to supplement the roofing pie with lining material. It will even out all the unevenness on the created plane and will act as an additional vapor barrier. Such material can be purchased at any construction market, but be careful, as there are quite a lot of them. In order not to make a mistake in your choice, it is best to read information about it on the Internet or ask for advice from experienced roofers.

Now let's figure out what material to create flat surface give your preference. I want to discuss moisture-resistant plywood and OSB material.

Oriented particle board has good performance: It is light, durable and costs quite little. But along with such qualities, there is the question of its environmental friendliness and high hygroscopicity. Such problems can only be corrected by high-quality insulation of this product from the main elements of the rafter system.

As for moisture-resistant plywood, experienced developers speak extremely positively about it. After the device roofing pie No critical deformations were observed with this material; in addition, the product tolerates a humid environment well. At first I started to think that it was perfect material, until my fellow roofers shared the terrible secret of this material. The fact is that during operation it begins to release harmful substances and in the event of a fire it can maintain combustion for a long time.

As you know, under the plywood there is a board, which is a kind of base for this material. Such wood can sometimes be used as independent sheathing. To do this, the boards are placed almost continuously, but there are gaps of 2-3 millimeters between them. This method creation is not recommended for creating sheathing on residential buildings, but as a alternative option For outbuilding quite suitable. It is worth noting that lumber is more expensive than plywood boards and is subject to faster rotting.

If you still prefer to use boards as the main material for lathing, then I advise you to take a closer look at calibrated products. Thanks to them, you can create an almost perfectly flat surface and, to remove all unevenness, lay a lining material on top of the boards. When purchasing wood, always give preference coniferous species. They are harder and stronger, therefore, can withstand increased load.

Requirements for sheathing under bitumen shingles

Whichever way you look at it construction industry, are present everywhere here regulations and installation and safety regulations. Without them, a person simply would not be able to build anything, and moreover, he would risk his life when going to work.

The sheathing for bitumen shingles must meet the following requirements:

The pitch of the sheathing under a soft roof must be less than 50 centimeters. Subsequently, the created surface is covered with plywood.
To create any elements of the rafter system, wood with a maximum moisture content of no more than 20% is allowed. If at the time of construction the lumber indicator exceeds this indicator, then it is necessary to leave them alone and allow them to dry to the optimum value.

The tree must be impregnated with antiseptics and fire retardants.
The sheathing boards must be smooth, without nicks or irregularities. To eliminate some defects, you can sand or plan the surface of the wood.
Before starting construction, carefully study the indicators of temporary loads, in particular snow and wind. Don't lose sight of the climate factor and average annual precipitation.
The pitch of the sheathing elements is directly affected by weight roofing. The larger it is, the smaller the step should be taken. IN in this case The weight of flexible tiles does not exceed 13 kilograms. Load from finished surface during precipitation on rafter legs it can reach up to 300 kilograms per square meter.
Its windage depends on the slope of the roof. The steeper the slope, the more strongly it is affected air masses, but the load from precipitation is significantly reduced. With a flat roof the situation is reversed. If you are planning to create a roof with minimum slope, then purchase thick and durable boards for constructing the sheathing.
After plywood in mandatory case Underlay carpet must be laid.

IMPORTANT: Bituminous shingles are distinguished by their capriciousness and even the slightest unevenness may later turn out to be main reason leaks.

The role of the drip line in the construction of a soft roof

Any construction field has its own nuances. Somewhere you have to work special tool, and install somewhere additional elements. When constructing a roof from bitumen shingles you have to deal with the need to install a drip. To explain in a nutshell, this is a sheathing element that protects eaves overhangs from negative impact precipitation.

The drip cap has curved shape, which directly depends on the slope of the slope itself. As a rule, the optimal bend lies in the range from 100 to 130 degrees. This element is located at the very edge of the roof slope, and its presence allows the rolling liquid to flow directly into the gutter. In addition to your direct functional purpose drip attached soft roof some grace.

When creating a drip tray on a soft roof, it is very important to remember the following nuances:

Its composition must necessarily include stainless metals, or coated with a high-quality protective layer.
By color, it is better not to distinguish this element from the overall picture of the roof.
Placing this element locally will provide virtually no benefit. If you have already decided to create a durable roof, then you should not skimp on this important object.

If you don’t know how to install a drip with your own hands, then after reading the technology of its design, I hope no questions will arise.

The drip line is fastened directly to the strongest sheathing board, and the other side is directed into the gutter.
This element is sold in a fixed length, which does not exceed 2 meters. It is necessary to join the droppers using the “overlapping” technique, which is about 10-20 centimeters.
So that the edges of the sheathing are under reliable protection they are covered with front strips.

You can purchase a ready-made drip pipe at any construction market.