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Plywood is a high-quality and inexpensive roofing sheathing!

Have you decided to lay a soft roof? Take care of high-quality continuous sheathing. And for this you don’t have to spend money on expensive material. Ordinary low-grade coniferous plywood will ideally cope with the assigned task. Let's figure out right now how to choose the thickness of plywood and how to lay it correctly so that the roofing pie reliably serves you for many years, protecting your home from bad weather.

This week's best prices for plywood!

Plywood for roofing - the main advantages over analogues

installation of roof sheathing using plywood sheets

For lathing, birch and coniferous fsf plywood (moisture resistant), as well as fc plywood, are most often used. When compared with other building materials, such as, for example, chipboard or OSB, installing plywood for roofing has a number of obvious advantages:

Plywood is stronger and more durable, the fibers in its layers are arranged perpendicularly, which means your roof will withstand significant mechanical loads;
Plywood is moisture-resistant (its price differs little from the price of ordinary plywood), but thanks to processing with special compounds, this material provides excellent resistance to water and moisture.
If you are interested specifically inexpensive material for the installation of roof sheathing - it will be 100% plywood. The price depends on the size, density and thickness.

Attention! The use of FK (waterproof) plywood for roofing is not always acceptable. In some climatic conditions this will lead to its delamination in the first 2 years and will require full analysis roofing and laying the entire covering again, and this is a colossal expense!

How to choose the right plywood thickness?

As you know, 10 mm plywood is most often used for roofing. However, a thickness of 9 to 12 mm is acceptable (a more specific indicator depends on the sheathing). Optimal sizes substrates (for plywood 10) – 3000*1500 mm. Using such sheets, you get maximum strength and minimum seams. This means you provide better hydro- and vapor barrier and durability of the roof. It is better to treat the ends of the sheets with oil or acrylic paints before installation.

Plywood 20 and plywood 18 are also used when installing the roof. Optimal parameters roofing structure is calculated depending on:

snow loads;
the weight of the roofing materials themselves.

For example, with a rafter pitch of 500 mm. For the construction of the sheathing, a 20 mm board is used. or moisture-resistant plywood 10 mm. If the pitch is 1200 mm, then use a 30 mm board or 20 mm moisture-resistant plywood.

Comparative characteristics of the thickness of materials for continuous sheathing

Rafter/Lathing spacing, mm	OSB-3 thickness, mm	Thickness of FSF plywood, mm	Board thickness, mm

Where to buy good quality plywood in Moscow?

So, you already know exactly what roofing material will be laid on your roof, you have chosen the thickness and dimensions plywood sheets for lathing. All that remains is to find an affordable supplier to buy plywood at favorable price. Remember that products high class and quality must always be strictly certified. If you purchase plywood in Moscow, then when purchasing it is better to familiarize yourself with all the attached certificates. We implement regular and laminated plywood, the price of which is 17-20% cheaper than competitors thanks to established cooperation and wholesale supplies from factories.

sheathing installation diagram

The main rules for installing plywood roofing sheets:

Before installation, roof rafter structures are carefully treated with varnish;
The flooring begins from below, gradually moving upward;
The distance between fasteners should be no more than 150 mm;
The edges of the slabs (that is, the places where they are joined) must necessarily rest on the rafter beams;
All subsequent plywood rows must move in comparison with the previous ones;
The plywood sheets are secured exclusively with screws. If you leave protruding caps on the roof surface, they will break through the roofing felt.

Attention! Coniferous plywood is impregnated with resins at the production stage. In addition to this, phenol-formaldehyde is used when gluing layers of material. This technology provides high resistance to rotting and fungi, which is especially important for humid climatic conditions.

Please note that during the warm season Construction Materials expand, which means that when installing plywood under the roof, it is necessary to leave gaps (2-3mm) in the seams of the lower skin in order to reduce depreciation and warping of the entire roofing structure.

If you do not have construction skills, it is better to entrust the installation of the roof to experienced professionals who know all the intricacies correct installation and will do 100% high-quality installation.

The reliability of a roof covered with soft tiles is ensured by correct design sheathing bases. Of course, it is no secret that it must be solid, moisture-resistant, smooth, unbending, and have a surface free of nicks and chips. But practice shows that the correctly selected material for the frame is not enough; it is also necessary to master the intricacies of installation technology and know how to properly attach the sheathing.

Sheathing for soft tiles: device options

There are several basic technologies for installing lathing. The simplest of them is a continuous sheathing under bitumen shingles, which is laid directly on the rafters. This technology is not used very often due to its lack of efficiency. Much more common is the method in which beams or boards are first secured to the rafters at an angle or parallel to the ridge, and then plywood or OSB is installed on them.

According to another method, it is attached to counter-lattice beams, which are fixed to the rafters, parallel to the rafters. Thanks to this base, a ventilation gap is formed under the continuous sheathing, starting from the eaves. The air, “enriched” with moisture, is discharged outside through the ridge. This makes it possible to support optimal humidity cover sheathing and other wooden roof elements and protect them from rotting and other damage. This type of configuration also makes it possible to install a layer of insulation and a superdiffusion membrane laid on the rafters.

There is another significant point, if the lathing is under flexible tiles will be installed with errors, then the manufacturer roofing material, despite defects in the roof surface, has the right to refuse to fulfill warranty obligations.

Which material to choose

Roofing plywood
Waterproof plywood is one of the most common materials for continuous sheathing. It is moisture resistant and flexible. To these characteristics it is also worth adding the multi-layer coating in order to understand what determines the high functional qualities of such sheathing and long term her services.

The optimal type of plywood used for sheathing is FSF plywood. She -

made from coniferous trees;
has high strength, including bending strength;
moisture resistant;
resistant to aggressive environments;
has a relatively light weight;
Thanks to treatment with special compounds, it has fairly good fire-resistant and antiseptic properties.

OSB-3 boards
By structure OSB boards fundamentally different from plywood or chipboard. Computerization technological process pressing minimizes the variation in thickness of OSB, so lathing under bitumen shingles from these slabs is very effective. They -

moisture resistant;
do not deform, do not warp from moisture;
sufficiently resistant to snow and wind loads;
are light in weight;
form a smooth, perfectly flat surface.

To install the frame under a soft roof, tongue-and-groove or edged boards from coniferous trees, sorted by thickness, are also used. , whose humidity does not exceed 20%.

Sheathing for flexible tiles: proper installation

When installing it, it is necessary to completely eliminate the possibility of sharp breaks and corners, otherwise excessive bending and friction of the roofing material cannot be avoided.

It is mandatory to adjust the materials used to install the sheathing under soft tiles– all its lines must be smoothed out as much as possible and made “soft”.

When using an edged board, the sheathing pitch for flexible tiles should be 3–5 mm. The boards are laid taking into account the direction of the fragments of the annual rings. They should be directed with their bulges upward. Why is this so important? If it is “driven”, the board will begin to unbend and, filling the gap between the slats, will have minimal impact on the roof. Otherwise, the arching will form a “hump,” which will completely disfigure the roof surface.

As additional measure, fastening a damp board is best done with two screws on each side.

The plywood is laid with the longitudinal side parallel to the ridge.

It is very important that the joining seams do not become a continuation of each other.

When installing in the cold season, the gap between OSB-3 boards, as well as plywood sheets, must be left at least 3 mm in order to compensate for linear expansion in warm weather.

Fastening of plywood sheets is carried out using rough nails or self-tapping screws. The caps of the fasteners are completely recessed to protect the top coating from damage. Fastening is carried out approximately in increments of 15 cm with the obligatory fastening of the edges of the sheets.

The thickness of the plywood sheets must correspond to the pitch of the rafters, sheathing or counter-lattice:

An underlay carpet must be laid on the installed continuous sheathing, and.

Installation of OSB-3 sheets is also carried out in a checkerboard pattern, with seams staggered, and secured using spiral nails (length 5.1 cm), ring nails (4.5 - 7.5 cm) or self-tapping screws. They are nailed to rafter legs ah or counter-lattice with a step of 30 cm, in the places where the slabs are connected, respectively - 15 cm at a distance from their edges of at least 10 mm.

In order to fix any type of roofing material on the roof, lathing is used. What it will be depends on the type of coating. IN this material We will talk about what the sheathing for soft tiles should be like and how to secure it correctly.

In essence, sheathing is a series of slats or other materials that are attached to the rafter system for subsequent laying of the finishing covering.

Main nuances and lathing scheme

The lathing scheme for flexible tiles can be of two types:

with gaps - for installation of hard coverings, for example, metal tiles, slate or corrugated sheets;
laid in a continuous layer - for flooring soft roof.

It is noteworthy that the installation of continuous sheathing for laying soft roofing is carried out in two layers. First, a lath or board is placed on top of the rafters at intervals, and then a continuous layer of sheathing made of solid OSB boards for a soft roof or plywood with moisture-repellent impregnation is attached to them. By the way, this finishing layer serves as additional sound and heat insulation.

Installation technology for sheathing and OSB under soft tiles

As with all other structural elements of the roof, installation of the sheathing must be carried out in accordance with the following rules:

A continuous covering of boards or sheets of moisture-resistant plywood is performed on pitched roofs with a slope of 5-10º.
On slopes with a slope of 10-15º, first a lathing for OSB is made on the roof from bars with a cross-section of 45×50 mm, laying them in increments of 45 cm parallel to the eaves, and then waterproof plywood or particle board is laid.
The same beams are also used on roofs with a slope of more than 15º, however, they are laid 60 cm from each other.
Additional sheathing bars are installed in places where the valley is attached to the ridge girder.

It is believed that the roof will last the longest if the soft roofing is laid on boards that are calibrated to the same size. In this case, the sheathing will be smooth, without differences in height, so that the joints can be perfectly adjusted. Consequently, on such a basis the coating will not be damaged ahead of time and will not lose its performance characteristics.

Edged coniferous boards are considered the most preferable for construction, combining low price and good performance.

When organizing sparse lathing for subsequent laying of soft roofing, the boards are laid with an indentation of no more than 10 cm. For a continuous type of sheathing, edged boards, particle boards and moisture-resistant plywood sheets are successfully used. Please note that installation of OSB under a soft roof must be carried out on strong boards, and its humidity should not exceed 20%.

Since the sheathing will be exposed to external influences, it must be strong enough to withstand:

increased snow loads in winter;
weight of the finishing coating.

Based on these conditions, perform the calculation structural elements roofs. In particular, if the pitch of the rafters for a soft roof is 50 cm, the sheathing is made from 20 mm edged boards or 10 mm waterproof plywood. When the rafter pitch increases to 120 cm, plywood with a thickness of 20 mm or a board with a thickness of 30 mm is used. That is, the thickness of OSB for a soft roof directly depends on the distance between the rafters.

Please note that wood, unlike soft tiles, is very susceptible to rotting and fungal development. Therefore, before installation, everything without exception wooden elements must be treated with an antiseptic.

Why do you need a drip line on the roof?

The drip edge is one of the required components of the sheathing. Its function is to protect the cornice from water leakage. This is important because it is in these places wooden structures most susceptible to rotting. Internal corner dropper can fluctuate between 100-130º depending on the steepness of the slopes. These elements are mounted on the edges of the roof, making sure that the water flows strictly vertically through them directly into the drain. In addition, the drip edge gives the entire roofing structure a more finished look.

Dripper characteristics:

such parts are produced from galvanized sheet steel with a polymer coating, which provides additional anti-corrosion protection;
color scheme the dropper should match the color of the main coating so as not to create dissonance;
drippers must be installed along the entire perimeter of the roof in order to equally protect the roof and façade from water leakage;
this element reduces windage pitched roof, this allows you to protect the structure from the wind.

Drip installation method

The technology for installing drips involves some nuances:

the main part of the drip is fixed on the sheathing board, while its lower section should be directed into the drain;
adjacent sections of steel droppers are laid overlapping each other;
additional protection the edges of the sheathing are provided by front strips;
at the next stage, they begin installing the roofing carpet, not forgetting to coat its edges with mastic so that it adheres better;
soft roof covering laid on top of the drip.

So, the sheathing is a very important element that allows for high-quality installation of soft roofing.

For a soft roof, two layers of sheathing are required, combined into a single structure.
The surface of the continuous sheathing should not contain differences in height or defects.
To avoid damage to the soft covering, all protruding sharp edges and bends must be rounded.
As a rule, edged boards with a width of 14 cm are used.
To prevent moisture from seeping into the space under the roof, the board should be laid with the tray facing up.
As well as sharp edges, the ends of the outer boards must be rounded so as not to damage the roofing material.
Antiseptic treatment will protect wood from pests and rot.
Wind strength in a particular region, as well as slope pitched roof, affect the pitch of the sheathing under soft tiles. As wind strength increases, the distance between the boards decreases.
Moisture-resistant sheets of plywood or particle board under a soft roof should be laid with an indentation of 1 cm so that when the material swells from moisture, it does not crack.
A drip cap will help protect wooden cornices and sheathing to prevent precipitation from flowing in.

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 they will be laid, so it is necessary to take the geometric parameters of the roof structure very seriously 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 pitched roof is also provided at the ends, 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. For rigid roofing sheets, the sheathing can be made from unedged 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 roof structures: mauerlat, rafters, ridge girder, 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, sheet material may over time bend, 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 point is the mechanical characteristics of the 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.
Despite all its rigidity, a board can “lead” over time, become warped, and the edges of individual boards can move out of the general plane of the surface. 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. As an option, 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 stretch a waterproofing membrane along the rafters, secure it with a counter-lattice made of timber with a section of 50 x 30 or 50 x 50 mm, and then 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 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 to installing a base for soft tiles should be the installation of a cornice strip or drip line.

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

Bituminous shingles are a modern, practical roofing material that is made from fiberglass impregnated with modified bitumen. It is light in weight and aesthetically pleasing appearance, resistance to environmental factors and the effects of fungi or other microorganisms. The peculiarity of this roof covering is that it does not have a rigid shape, so for its installation it is necessary solid foundation. Lathing for a soft roof is an important element of the roof structure, on which the durability and reliability of the material depends. In this article we will tell you how to properly prepare the base for laying asphalt shingles.

Sheathing is the base on which a roofing covering consisting of wooden bars or plywood is laid. It is nailed to the rafters of the frame to ensure strength and even distribution of weight. Bituminous shingles - lightweight material, 1 square meter which weighs up to 13 kg, but it needs a reliable base, as it does not hold its shape on its own. There are 2 types of sheathing construction:

Sparse. The sparse lathing is made from wooden blocks 3-4 cm thick or boards. The distance between these bars is called a step; for installing a soft roof it should not exceed 50 cm.
Solid. Solid sheathing is made from sheets of moisture-resistant plywood or particle board. It serves as an excellent base for laying bitumen shingles, thanks to its even, smooth surface.

Important! It is recommended to use wood for the manufacture of sheathing for flexible tiles coniferous species, dried to a moisture content of 20 percent. This material is more resistant to moisture, fungus and rot, which extends the life of the structure.

Design

The lathing used for installing a flexible roof differs from that used in the case of metal profile flooring. Bituminous shingles are a flexible material that does not have a rigid shape, so it must be laid on a solid base. Therefore, the design of the roofing pie for this roofing material consists of the following elements:

Counter-lattice. This item is made from wooden slats 2-3 cm thick, which are attached along the rafter legs. They serve to fix the waterproofing film and organize a ventilation gap, which is necessary to improve air circulation.
Sparse. The sparse sheathing is nailed along the slope, perpendicular to the rafters. It is made from unedged or edged boards measuring 150x20 mm in increments of 30-50 cm. The sparse lathing evenly distributes the weight of the roof between the rafters.
Solid. The continuous sheathing used as a base for laying flexible tiles is made from sheets of moisture-resistant plywood or particle board. This structural element, in addition to its supporting function, also performs an insulating function - it plays the role of insulation and sound insulation.

Note! Bitumen shingles have a rough, non-slip surface, so snow accumulates on them in winter. Reliable lathing will help the soft roof maintain its shape and withstand intense snow loads.

Requirements

The sheathing for a soft roof is made of wood, dried to a moisture content of 20% and treated with deep penetration antiseptic agents. In order not to damage the lower surface of the roofing material, knots, jags, and irregularities must be removed from the boards. It is better to sharpen or sand the sheathing elements. In order for the base to serve for a long time and reliably, the following factors must be taken into account:

Snow load in the area where construction is taking place. When choosing a design and spacing between bars, you must take into account climatic factor. If there is a lot of snow, then the base for installing flexible tiles must be strengthened.
Weight of roofing material. One square meter of bitumen shingle covering weighs no more than 13 kg, but together with insulation and waterproofing, the load on the rafters can exceed 300 kg/m2.
Roof slope. The lower the roof slope, the stronger the sheathing should be, since snow does not slide off the gentle slopes on its own, but accumulates, increasing the load on the rafter system.

Please note that even the slightest unevenness on the base as a result of friction leads to the appearance of holes in the bitumen shingles. To prevent this, the sheathing structure is made in three stages, and its surface is leveled using a building level.