Which lathing for flexible tiles is better - types and rules of construction. Features of roofing decking made of OSB slabs Single-layer lathing made of panel materials - pitch, frame thickness

Oriented strand board (OSB), when used inside a dry room, does not require any additional protection from moisture. The worst conditions are found on the outer cladding of a house made from this slab. Over time, it darkens not only from rain, but also from solar ultraviolet radiation. Of course, you can cover the slabs with siding or blockhouse, but this is associated with high costs. How to treat OSB boards against moisture is a difficult question. Let's try to answer it.

Is additional processing needed?

The moisture resistance of oriented strand boards is characterized by the amount of thickness swelling during the day. According to this parameter, according to the American standard PS 2, European EN-300 and Russian GOST 10632-89, slabs are divided into 4 types (see table).

Let us recall that for external cladding In buildings, only OSB-3 and OSB-4 boards are allowed.

If the constructed structure is to be finished somehow, then during construction the OSB boards lie on the construction site in bundles. Even after one rain, several top sheets swell almost one and a half times. They will remain like this after drying. The remaining sheets swell at the ends. By the way, to avoid this, the ends of North American products are painted with blood-red impregnation.

There is an opinion among some builders that OSB boards do not require additional processing, since they are already impregnated with resins, waxed, and varnished. Experience shows that after 2-3 years they appearance loses its original freshness, they darken, in some places individual chips bulge, joints protrude sloppily.

Therefore additional hydrophobic treatment will not be superfluous, especially if it is the facade of a residential building without any cladding. Let's consider how to treat OSB boards from moisture.

1. Transparent impregnations

Most cheap option treatments – water-repellent colorless impregnations. There are no special solutions for OSB. You can use any wood products, with the exception of those prepared on water based. Examples of such compositions:

Elcon silicone-based antiseptic impregnation for wood. Designed for long-lasting protection wooden structures from weathering, rotting, mold. Scope of application: for interior and exterior work. Forms a water-repellent film, non-toxic, allows the wood to “breathe”.
Innovative domestic hydrophobizing composition NEOGARD-Tree-40 based on organosilicon oligomers. Designed to impart water-repellent properties to products made of wood and wood-based materials: plywood, chipboard, fiberboard. Water absorption for chipboard is reduced by 15 - 25 times. Obviously, it is also suitable for OSB. Does not change the natural color of the material, the protective properties remain for at least 5 years.

The most suitable for protecting wood (and OSB) from moisture is the so-called yacht varnish on a urethane-alkyd or alkyd-urethane basis. Some of the popular brands:

Tikkurila UNIKA SUPER (Finland). This brand is a leader in resistance to impacts external environment, immunity to ultraviolet radiation and temperature changes.
Marshall protex (Türkiye). Creates a plastic surface film.
Marshall Protex Yat Vernik. It has increased wear and moisture resistance.
PARADE (Russia). Keeps fresh for a long time.
Belinka Yacht (Russia). It has dirt- and water-repellent properties, emphasizing the texture of wood materials.
Antiseptic varnish for wood “Drevolak” on acrylic base with added wax (Russia). Along with antiseptic and antibacterial effects, it successfully protects wood from moisture.

Since OSB is a wood processing product, then paints and varnishes(LMB) the same ones can be used for them:

Oil paints. Due to the presence of polymer resins in OSB, drying oil-based paints do not always adhere well to the surface being painted. For better adhesion to the base, it is recommended to perform double priming with intermediate putty before painting. Despite this, oil-based coatings under the influence of ultraviolet radiation, temperature changes and precipitation are prone to fading, cracking, and even peeling. We can recommend paint based on natural and modified oil PINOTEX WOOD OIL SPRAY, which has good resistance to external factors.
Alkyd paints are better suited to particle boards because they contain alkyd resin, a product of the chemical reaction of natural oils with acids. Their adhesion is higher compared to oil-based paints, they dry faster and resist atmospheric influences more successfully.
Acrylic compositions, being inexpensive and durable in operation, differ optimal ratio qualities and are most in demand for painting wood. In addition, they are available in a wide range of colors.

Attention: pre-treat a small surface in an inconspicuous place to ensure that the material does not swell when exposed to the aqueous acrylic suspension.

In conclusion, we can say that the question: how to treat OSB boards against moisture is difficult to answer unequivocally. Firstly: it depends on whether you want to emphasize the texture of the slab with a transparent solution or, conversely, apply a covering (opaque) coating. Secondly: – on the financial capabilities and aesthetic ideas of the developer.

Good afternoon
We are building frame house, it is covered with OSB boards, there is a roof - corrugated sheets, it will go into winter in this form. During the summer, after several rains, the OSB delaminated in some places. Is it possible to cover the walls with windproof film for the future ventilated façade for the winter and will it not lose its properties by spring? And what material is better to take: Izospan A, AD? The facade will be a blockhouse.

Cover up an unprotected façade windproof film it is possible, but this will not completely solve the problem of preserving OSB. The fact is that the windproof membrane is designed to withstand the impact of individual drops, which are the result of condensation on the roofing. Good slanting rain, downpour, wet snow is beyond its power, the windproof membrane will “cry” with inside. Undoubtedly, wind protection will reduce the wetting of the OSB, but will not completely eliminate it.

A windproof membrane is a good thing when it is covered with exterior finishing

OSB-3 boards, which will most likely cover the frame of your house, can only be called moisture resistant with a stretch. And then we can talk about their resistance to moisture only in relation to chipboard, fiberboard, OSB-1 and OSB-2, which quickly deteriorate under the influence of water. OSB-3 is not intended for use as fencing wall material without further finishing, unlike, for example, cement particle boards(DSP). By the way, in Canada and the USA, where they came to us from frame technologies, for finishing decent houses that should last a long time, they use waterproof plywood, particle boards are the lot of the poorest.

Manufacturers provide such characteristics as the degree of swelling of an oriented strand panel when placed in water for 24 hours. For OSB-3 it is 15%. This is not so little, contrary to the claims of sellers and manufacturers. Of course, on the walls the particle boards are in a vertical position and are only exposed to slanting rain on one side. However, let’s assume that there are showers, sleet, and humidity for a week or two. Low air temperatures and the absence of sun do not allow the walls to dry.

Unprotected from precipitation OSB sheets properly soaked and swollen. At the same time, they will increase not only in thickness, but also in length and width, albeit not so significantly. As a result, the particle boards, rigidly fixed to the frame, will warp. And it is not a fact that when they dry they will return to their original shape; residual deformations are very likely. In addition, the fastening points will weaken, delamination of the ends may occur (it has already begun for you), and the strength of the gluing will decrease. Hardly in one season particle boards no critical damage will be caused, but their service life will be shortened, the overall stability of the frame will decrease, this is a fact.

OSB is not a completely waterproof material; it will inevitably deteriorate if exposed to moisture for a long time.

In our opinion, the following options are possible for temporary protection of an unfinished facade from precipitation:

Pull windproof membrane Izospan A (18 RUR/m2) on a vertical sheathing, use a block 4-5 cm thick. The film is quite weak, it is not a fact that it will successfully survive the winter and will not be torn by the winds.
Use Izospan AM (24 rubles/m2) or Izospan AS (35 rubles/m2). Three-layer wind protection is stronger, less permeable to water vapor, but three times more water-resistant, which means it will get wet less. Under the finishing (blockhouse) it could be stretched without lathing, directly over the slabs. But in your case, a ventilated gap and sheathing are needed. It is necessary to ensure free flow of air, the gap should be at the bottom and at the top, under the roof. Option #2 is preferable.
Stretch any cheaper vapor-waterproofing material over the sheathing, maintaining ventilation: roofing felt, reinforced construction vapor barrier, dense plastic film for greenhouses (enough for one season). When covering the facade, the waterproofing will have to be removed.

While there is no finishing, polyethylene film, with or without reinforcement, can be used as temporary protection

The right decision would still be to tighten up with finances and finish by the fall exterior finishing, covering the facade with a blockhouse along a vertical sheathing. In the end it will be cheaper, because they can serve as windbreaks themselves. OSB boards, if they fit neatly. You won't have to spend money on film.

Correct solution"puff pastry" frame wall. If the OSB boards fit well and the insulation is completely closed, they will also serve as wind insulation. There is no need to spend money on an additional membrane.

02.12.2012, 21:08

Dear forum members, I need advice. For the winter, the roof remains under 9mm OSB. The house is made of gas silicate, there is a rafter covered with a Eurovent membrane, covered with a counter-lattice, lathing with a pitch of 30 cm. On top of 9mm OSB. A valley carpet is partially laid, the roof is accordingly not insulated and the house is not heated. The roofers, having received half the money for the entire turnkey roof, refused to carry out further work, citing bad weather.
Help me make the right decision.
1 Cover the roof with cellophane nailed down with slats (there are fears that moisture from the OSB under the unventilated cellophane will destroy the OSB)
2 Cover the roof with some inexpensive membrane that allows air to pass through and retains water.
3 Bring in a new team and cover with flexible tiles until the snow and frosts are finished (the confusing thing is that the base of the OSB is wet and under the sealed tiles it will trample and become deformed, then collapse)
4 Leave everything as is. But none of my friends have experience with how uncovered OSB survives.
The old roofers say to wait for spring and not cover anything, the new team - they really need work - they say that you can put it on wet and down to -5 below zero with a hairdryer.
I would like to hear the objective opinion of a disinterested specialist, thanks in advance

Good afternoon
We are building a frame house, it is covered with OSB boards, there is a roof - corrugated sheets, it will go into winter in this form. During the summer, after several rains, the OSB delaminated in some places. Is it possible to cover the walls with windproof film for the future ventilated façade for the winter and will it not lose its properties by spring? And what material is better to take: Izospan A, AD? The facade will be a blockhouse.

It is possible to cover an unprotected façade with windproof film, but this will not fully solve the problem of preserving OSB. The fact is that the windproof membrane is designed to withstand the impact of individual drops, which are the result of condensation on the roofing. Good slanting rain, downpour, wet snow is beyond its strength, the windproof membrane will “cry” from the inside. Undoubtedly, wind protection will reduce the wetting of the OSB, but will not completely eliminate it.

A windproof membrane is a good thing when it is covered with exterior finishing

OSB-3 boards, which will most likely cover the frame of your house, can only be called moisture resistant with a stretch. And then we can talk about their resistance to moisture only in relation to chipboard, fiberboard, OSB-1 and OSB-2, which quickly deteriorate under the influence of water. OSB-3 is not intended for use as an enclosing wall material without subsequent finishing, unlike, for example, cement-bonded particle boards (CSP). By the way, in Canada and the USA, where frame technologies came to us, to decorate decent houses that should last a long time, they use waterproof plywood, particle boards are the lot of the poorest.

OSB sheets that are not protected from precipitation will get wet and swell. At the same time, they will increase not only in thickness, but also in length and width, albeit not so significantly. As a result, the particle boards, rigidly fixed to the frame, will warp. And it is not a fact that when they dry they will return to their original shape; residual deformations are very likely. In addition, the fastening points will weaken, delamination of the ends may occur (it has already begun for you), and the strength of the gluing will decrease. It is unlikely that particle boards will not suffer critical damage in one season, but their service life will be shortened and the overall stability of the frame will decrease, that’s a fact.

OSB is not a completely waterproof material; it will inevitably deteriorate if exposed to moisture for a long time.

In our opinion, the following options are possible for temporary protection of an unfinished facade from precipitation:

Stretch the windproof membrane Izospan A (18 RUR/m2) over the vertical sheathing, use a block 4-5 cm thick. The film is quite weak, it is not a fact that it will successfully survive the winter and will not be torn by the winds.
Use Izospan AM (24 rubles/m2) or Izospan AS (35 rubles/m2). Three-layer wind protection is stronger, less permeable to water vapor, but three times more water-resistant, which means it will get wet less. Under the finishing (blockhouse) it could be stretched without lathing, directly over the slabs. But in your case, a ventilated gap and sheathing are needed. It is necessary to ensure free flow of air, the gap should be at the bottom and at the top, under the roof. Option #2 is preferable.
Stretching any cheaper vapor-waterproofing material over the sheathing while maintaining ventilation: roofing felt, reinforced construction vapor barrier, thick polyethylene film for greenhouses (enough for one season). When covering the facade, the waterproofing will have to be removed.

While there is no finishing, polyethylene film, with or without reinforcement, can be used as temporary protection

The right decision would still be to tighten up with finances and finish the exterior finishing by the fall, covering the façade with a blockhouse along a vertical sheathing. In the end, it will be cheaper, because the OSB boards themselves can serve as wind protection if they are carefully fitted. You won't have to spend money on film.

The correct solution for the “puff pastry” of a frame wall. If the OSB boards fit well and the insulation is completely closed, they will also serve as wind insulation. There is no need to spend money on an additional membrane.

There are many varieties of soft roofing. This includes numerous rolled fused materials, soft tiles and roofing felt. These materials may have different operational and visual characteristics, but they also have a common feature - they are all made on the basis of bitumen, which ensures the softness and flexibility of the final product.

For all its flexibility, a soft roof can retain the shape once given to it and withstand various loads - but in order for these properties to manifest themselves, it is necessary to install high-quality and reliable sheathing under the roof. About how to make a sheathing under soft roof, and will be discussed in this article.

Types of lathing for soft roofing

There are two fundamentally different types– solid sheathing and lattice. In a lattice sheathing, all elements are located at some distance from each other. As a rule, the pitch of installing boards in such a sheathing varies from 20 to 50 cm. This design is not suitable for soft roofing materials - the gaps between the boards are too large, so the roof will sag in them.

A completely different matter is a solid sheathing, in which, as the name suggests, there are no gaps between the elements or are reduced to a minimum. Maximum sheathing pitch under flexible tiles in this case it is 1 cm.

Two types of continuous sheathing can be installed under a soft roof:

Single layer. In this design, the sheathing elements are installed directly on the rafter legs and are located parallel ridge run. For installation of single-layer sheathing, boards, moisture-resistant plywood or OSB are suitable. This design is used quite rarely and only if the roof is covered with roofing felt.
Double layer. This type The lathing consists of two layers, which can be made from the same material or from different ones. First, a rafter system is installed under the soft roof, then the first layer is arranged as a lattice, with a rather large step in installing the elements. A second layer is mounted above it, in which gaps are not allowed. The main advantage of a two-layer sheathing is the presence ventilation duct and free space sufficient for installation thermal insulation materials, which makes this design very convenient for arranging a soft roof.

The installation technology of each type of lathing is worth considering in more detail.

Single-layer sheathing made of boards for flexible tiles

As mentioned above, a single-layer sheathing for flexible tiles is attached directly to the rafters and is only suitable for laying roofing felt. In addition, when using such a design, it will not be possible to install insulation, so from the point of view of energy efficiency, single-layer sheathing is not very good.

The frame for a soft roof can be made of tongue-and-groove boards or planks. Choose unedged boards extremely undesirable - any roughness and unevenness of this material will certainly lead to deformation of the soft roof, which, in turn, will lead to a decrease in their decorative and performance characteristics.

When choosing boards, you need to take into account the following requirements:

The material must be smooth and smooth surface without any irregularities;
The width of the boards can vary between 100-140 mm, and the thickness - 20-37 mm;
The humidity of the boards should not exceed 20% (excess moisture in the wood leads to its premature deformation and damage roofing);
Before making the sheathing, everything wooden elements it is necessary to impregnate with antiseptics that will protect the wood from rot, mold and pests.

Structurally, the single-layer sheathing under consideration consists of boards that are packed to the rafters close to each other. The boards must be placed parallel to the ridge. To prevent them from warping over time, they need to be laid with the concave side up, so that moisture that has made its way through the thickness of the roofing will flow out along the boards through the cornice.

It is necessary to begin the process of installing the sheathing from the eaves overhang, gradually moving towards the ridge. The length of the boards must be selected so that they fit exactly on the rafter legs. It is advisable to fasten them as close to the edge as possible, driving nails into the wood up to the head.

The optimal gap between vertical adjacent boards is 3 mm. The presence of such a gap, on the one hand, will ensure reliable support for a soft roof, and on the other hand, it will allow the boards to freely change their sizes with changes in temperature and humidity. If you fix them more tightly, then constant expansion and narrowing the boards will sooner or later lead to their curvature.

Single-layer lathing made of panel materials - pitch, frame thickness

To arrange the sheathing, you can use not only boards, but also panel materials - plywood or OSB. They have everything necessary qualities, which are required by a quality support structure. In addition to good performance characteristics, plywood for flexible tiles is easy to install and has an initially flat surface, ideal for further installation of soft roofing.

The panel materials used in single-layer lathing are also subject to a number of requirements:

High moisture resistance. A soft roof must be reliably protected from moisture, so it is necessary to select moisture-resistant materials for the sheathing. If we talk about specific brands, we can highlight OSP-3 and FSF.
Suitable thickness . Panel materials can have a thickness from 9 to 27 mm (choice specific value depends on the pitch of the rafters).
Antiseptic treatment. In order for the lathing made of panel materials to be sufficiently durable and reliable, it must be treated with an antiseptic before installation.

Laying panel materials on rafters is done differently than with boards. The sheets are mounted parallel to the ridge, but their joints should not coincide. Typically, a staggered arrangement is used for such material.

Adjacent sheets should be 2 mm apart from each other. When installing the roof in winter, the pitch should be increased to 3 mm so that the sheathing can freely expand in the summer. To fix the panels, self-tapping screws or nails are used, which are used as follows: on the rafters the fastening step is 30 cm, at the end sections they are located 15 cm from each other, and at the edges - 10 cm.

Double continuous plank sheathing

A two-layer sheathing consists of two layers, one of which is made in a lattice form, and the second, located at the top, is solid. This lathing design is more reliable and efficient than a single-layer one, so it is used in the vast majority of cases. Of course, due to the greater number of layers, the thickness of the soft roof increases.

In the embodiment under consideration, each layer of the sheathing consists of boards that must meet the following requirements:

The lattice layer boards must have a thickness of over 25 mm and a thickness of 100 to 140 mm (instead of boards, beams with a section of 50x50 or 30x70 mm can be used);
To make a continuous layer of sheathing, boards 20-25 mm thick and 50-70 mm wide are required;
Before installation, wooden elements must be treated with antiseptic agents.

Installation of a two-layer sheathing is quite simple. First of all, boards of the first layer are fastened parallel to the ridge across the rafters. They need to be secured at such a distance that the second layer does not sag after installation. Optimal step installation of boards of the first row - 20-30 cm.

When the first row is installed, you can begin installing the second. The sheathing elements must be installed from top to bottom. A small gap of 3 mm should be left between the boards for normal thermal expansion.

Combined two-layer roof sheathing

Best suited for laying flexible tiles combined option sheathing, in which the first layer consists of sparse boards fixed perpendicular to the rafters, and the second layer is made of panel materials. This type of construction is standard and is most often used when arranging an unheated attic.

To create an insulated attic with waterproofing and insulation, you will need a different scheme, somewhat more complex. First, you need to fill the counter-lattice along the rafters, and then all the other elements will be attached on top of it. Let's figure out why the counter-lattice is needed in general. The counter battens allow you to create a ventilation gap between the main batten and the waterproofing material.

The materials used must meet the following requirements:

For the counter-lattice, even bars with a cross-section of 25x30 or 50x50 mm are suitable;
The first layer is made of boards 25 mm thick and 100 to 140 mm wide;
Plywood or OSB under soft tiles must have a thickness of 9 to 12 mm;
All wooden elements must be impregnated with an antiseptic.

Installation of the combined sheathing is carried out according to the following algorithm:

When settling in warm roof With insulation and waterproofing, you need to install a counter-lattice, which is attached above the rafter legs. In addition to creating a gap for ventilation roofing pie, counter-lattice bars provide fastening of the waterproofing film. To create such a structure, you first need to install thermal insulation and waterproofing, and only then begin installing the sheathing.
Next comes the turn of the boards of the first row, which are attached to the counter-lattice (if there is one) or directly to the rafter legs. The standard step for attaching the bottom layer of the sheathing is 20-30 cm.
Lastly, the last row of sheathing is installed. Sheets of the selected material are laid in a checkerboard pattern with a small gap (2-3 mm). OSB or plywood for soft tiles is attached to each rafter leg with a pitch of about 30 cm. The edges of the elements should also rest on the supports, and at these points the fastening step should be reduced to 15 cm.

Checking the quality of the sheathing

If the sheathing is under bitumen shingles was installed correctly, it will have a number of properties:

No deflection under human weight - sagging elements of the sheathing will significantly complicate the installation of the roofing and its repair;
No gaps beyond acceptable limits (if there are large gaps in the sheathing, they must be sealed with roofing sheet);
No irregularities, protruding nails or knots that could compromise the integrity of the soft roofing material;
No sharp edges around the entire perimeter of the finished sheathing;
Well-conducted preliminary preparation wood, which includes drying boards and sheets, as well as impregnating them with antiseptics.

The roof sheathing for a soft roof is considered complete only if it meets all the described requirements.

Conclusion

Several types of lathing are suitable for a soft roof, so before you make a lathing for a soft roof, you need to choose suitable design. If all the nuances have been taken into account, then all that remains is to correctly carry out installation work, And finished design will provide reliable support for soft roofing.

OSB boards are boards with flat chips that are suitable for all kinds of construction work, as well as for roofing. Such roofing slabs consist of 95% coniferous or aspen wood. High-quality slabs are presented on the page http://www.sferastroy.ru/e-store/goods/osp_3_plity_osb_3/. To make this material, a binding composition is used, which can glue the chips together and give them moisture-resistant properties. The adhesive used to make the pox panel is environmentally friendly. After the technological process, additional processing is also carried out, which enhances operational properties OSB boards. The advantage of these plates is that they combine low cost with excellent quality.

Moisture-resistant boards for roofing are so far best option when creating a roof. After all, a roof covered with OSB boards not only has a wonderful appearance, but it also perfectly withstands the vagaries of the weather. An OSB roof can easily withstand strong winds, rain, scorching sun and even snowdrifts. Besides. OSB for roofing fully complies with all standards and modern rules construction, and they are characterized by extraordinary durability. Such slabs are produced in the USA and Canada, and their further sale is carried out through a huge network of regional warehouses.

Construction boards made of OSB for roofing are also suitable as flooring, they are especially good for installing flexible shingles tiles. It is important that the sheathing of such OSB boards has a flat and smooth surface, this makes it easier technological process installation of many building materials. The OSB board has a rigid base; it is not subject to deformation when exposed to moisture. And thanks to its chip structure with a cross-shaped orientation, this construction material can be attached very securely to the roof frame.

OSB board is great for roofing works thanks to the fact that it is easy to give it right size and shape, as it is easy to saw. The thickness of such a slab is calculated taking into account snow loads and sheathing pitch. The main qualities of OSB boards are considered to be: uniformity, rigidity, durability, and excellent sheet geometry. Fiber direction quality slabs OSB should be perpendicular to the main beams. OSB especially large sizes cover almost the entire distance between the supports and at the same time they maximize the reliability of the entire roofing structure. OSB boards are significantly superior physical and mechanical properties plywood, which is why it is considered more suitable material with continuous roofing.

Lathing is an integral part of the roof structure; the durability and design of the entire roof depends on it. Since the types of roofing decking are different, the sheathing for them is also made differently. For example, a continuous sheathing is made under a standing seam or finished roof. The flooring must have increased strength and density, smoothness and uniformity of the surface. It is because of this that OSB for roofing decking is considered the optimal decking that meets all quality standards.