How to put OSB on the floor

Making OSB floors on the joists

Most types of flooring materials produced today, for installation require the creation of a solid, even base. In most cases, as such make the device of concrete or sand-cement screed in the house. However, there is a decent alternative, which is to install OSB boards (OSB) on wooden joists. The result is a solid, even subfloor suitable for any flooring. What is peculiar about OSB, which can replace the concrete screed? On this, as well as ways to install OSB on the joists with their own hands will be discussed in this article using information in video format.

laying of the OSB subfloor

Direct laying of ceramic tiles must be preceded by thorough preparation of the OSB subfloor. If necessary, the material can be laid directly on the floor slab or on a strong old boardwalk.

Stored planks become stronger, less prone to warping and drying out, so they can be a good basis for chip boards, but the existing floor of wooden boards must be carefully checked, treated with antiseptic and replace rotten elements (boards, substrates, joists). The basement is insulated with glass wool, leaving a small air gap under the floor itself.

The subfloor should be levelled with underlayments as much as possible. Underlay and OSB boards must be separated by a small distance to ensure free passage of air. Also special holes can be drilled for ventilation.

The most rational variant. laying OSB on the joists. The installation process is not difficult, but requires the careful observance of some points:

  • The floor is lined with waterproofing: dense polyethylene or special roll materials.
  • The beams are treated with antiseptic substances for protection against mold. The spacing is determined by taking into account the planned finish flooring.
  • The space between the beams is filled with either a layer of expanded clay or insulation material (for example, mineral wool) for soundproofing and insulation.
  • The OSB is laid. The joints of the boards should be directly on the joists, and the gaps between them. Boards are fastened with self-tapping screws.
  • Ceramic tiles require a particularly solid foundation, so laying OSB in two layers, with the upper boards overlapping the joints of the lower ones.
  • According to the technology it is required to leave a small space between OSB boards and the walls, in order to avoid deformation of the material due to temperature changes.

Installation of an additional layer

Gluing tile directly on the OSB is useless, as it will not adhere well to the surface of OSB. You can lay it as on plywood, using a special grid and glue, but this technology does not guarantee the longevity of the coating.

Using mesh, the tiles were glued to the OSB and literally a day later the tiles fell off.

The best option would be to install additional flooring, which provides the best basis for laying.

To create such a layer is used glass magnesite or cement-bonded particleboard, the surface of which is covered with a fine crumb and is perfectly suitable for gluing tile.

Additional trim is firmly attached to the OSB with screws (as shown in the photo above), for greater strength using construction adhesive, and the cement-bonded particleboard is laid in the direction opposite to the main coating. Small gaps are left between the sheets, near the walls.

Tools and materials for work

The list of necessary devices is minimal:

  • crowbar-nailer;
  • hammer;
  • Peorator, drill, drill bits;
  • an electric screwdriver;
  • A large bubble or laser level (with the second tool will be more convenient to identify irregularities).

Choosing this method of “reanimation” of old wooden floors, you need to have an idea about the material used for this purpose in order to choose it correctly. The result of alignment directly depends on it.

OSB on the old wooden floor: installation of boards

Before you start the work, it is necessary to dry and cure OSB plates in the room. at least 2 days. If you make a good preparation of the substrate, then the laying of boards will not be much of a problem. Depending on the condition of the old wooden floor there are two options for laying OSB: on boards or on the joists.

Laying on the boards

Works are performed in the following sequence

  • rolled vapor barrier membrane, which will prevent the floor from condensation during operation;
  • OSB boards are laid out in the room with an offset of joints of at least 1/3 of the length of the element and marked for further cutting. this will eliminate errors and misalignment when fastening;
  • The boards that come close to the wall are cut off according to the marks;
  • Board installation begins from the corner with a gap to the wall of at least 10-15 mm, the gap between the boards. 5 mm. These gaps compensate for thermal expansion of the materials and prevent bulging;
  • OSB is fastened with self-drilling screws, the places for which are countersinked to ensure that the flats are sunk;
  • screwing rules. screws are screwed in from the edge of the board to the fastening area in at least 5 mm, the distance between the screws is 30 mm, the distance between the rows is 60 mm, screws are screwed in first around the perimeter of the board, then in the center. It is worth taking into account the location of the board under the boards. the hardware should not get in the gap between the old boards;
  • the expansion joints are filled with assembly foam, which is cut flush with the surface of the subfloor after it dries.
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Laying on the joists

Installation of OSB on joists is carried out using the same principles as on the boards. However, there is a certain peculiarity.


The presence of spacing between the joists significantly reduce the load-bearing capacity of the OSB subfloor. Therefore to create a solid foundation in this case requires, above all, the use of thicker boards. It is also worth reducing the spacing of the joists by adding them. If there is no possibility to increase the number of beams, additional subflooring made of boards with the required spacing can be installed. However, this will significantly increase the financial costs.

Despite its popularity, the technology of laying OSB boards when repairing a wooden floor, it is far from an ideal option. There are a number of disadvantages, due to which the owners may have problems with OSB on a wooden floor.

Despite the special impregnation, with high humidity in the room, such as in a bathroom or kitchen, the boards can swell, deform, and the wooden base begin to rot.

With high strength, OSB. the material is too flexible. The floor is the most stressed surface in the apartment, and if the substrate is not rigid enough, it will sag over time.

Due to the flexibility and permanent movement of the boards and planks, squeaks appear when walking on the floor over time.

Significant concentrations of formaldehyde resins are harmful to the human body.

Because of these drawbacks significantly reduces the service life of the floor, which will lead to premature repair, despite the fact that the flooring itself can serve for many years to come.

Besides this, the rough surface of OSB is not suitable for all floor coverings, and installing it directly on an old wooden floor reduces the height of the room.

Despite the fact that the quality of oriented chipboard is superior to that of particleboard, this construction material is not suitable as a finish flooring:

  • it is necessary to leave a gap of 2. 5 mm between the sheets to avoid squeaking during temperature expansion;
  • joints are caulked with sealant, reduce the aesthetics of the design of the covering.

That is why OSB is mostly used as a subfloor:

  • Boards have perfect flatness, which allows you to level with them deformed from the long use of tongue and groove board floorboards;
  • The continuous surface of OSB is suitable for small-format coatings, which cannot be laid on a loose board without disturbing its flatness;
  • the boards have stable geometry and self-supporting capacity, so they can be used to reinforce a rough floor with sparse joist spacing or small floorboards to increase its spatial rigidity and load-bearing capacity.

After installing OSB the surface is even and has a high load-bearing capacity.

You need to know how to properly attach OSB sheets to floorboards/layers, use offset joints in adjacent rows.

There are several types of oriented chipboard:

Important! Since the subfloor has a low repairability, it is forbidden to use OSB-2. Boards are additionally treated with antiseptic and waterproofing material.

The main characteristics of oriented strand boards are:

  • density. 630 kg/m³;
  • thermal conductivity. 0,13 W/mK;
  • Linear expansion. 0.15% at 70% humidity;
  • straightness. 0.6 mm/m;
  • perpendicularity of the opposite sides of the sheet. within 3 mm;
  • thickness deviation. 0.3. 0.8 mm (sanded, untreated, respectively).

Advice! Manufacturers produce boards of different sizes, which should be taken into account when buying, in order to reduce the waste of cutting for specific dimensions and configuration of the room.

Installation technology

In order to properly lay the sheet material over the existing boardwalk, it is necessary to meet the conditions:

  • Basement revision. rotten joists and boards are replaced, creaks are eliminated, thermal insulation, vapor barrier membrane and waterproofing underneath are checked, impregnation of boards with antiseptic and fire retardant is renewed;
  • layout. usually from the long wall, the offset of joints in adjacent rows at least 30. 40 cm;
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Important! When installing parquet, PVC-tile and other small-format coatings the screw heads must be puttied.

Laying recommendations

Depending on the type of finish flooring the OSB boards are not oriented the same way on the wooden floor:

  • for small-format decorative materials it is necessary to provide that the joints of tiles, PVC tiles do not coincide with the joints of OSB boards
  • when choosing laminate, tongue and groove, decking or flooring, it is better to lay rows of OSB across the direction of long-length finish layer cladding or at an angle of 45 degrees for diagonal layout (relevant in rooms with defects in wall geometry).

Advice! It is allowed to lay screed of CPS or selflevelling floor on OSB. However, the surface of oriented strand board should be pre-treated with a waterproofing material to avoid leaks into the ground floor and swelling of the construction material itself.

How To Install OSB Subfloor

Repair of finish flooring

The main problem with the boardwalk is a floorboard or a few boards that develop a transverse “hump” when the humidity changes periodically or during the drying process. This leads to an increased repair budget:

  • The surface of the floor becomes uneven “comb”;
  • OSB does not rest on the floorboards with its whole surface, but only in places where it touches a “hump”;

In other words, you should use OSB 22 mm or thicker. This problem can be solved by sanding or scraping the subfloor beforehand:

  • A sanding machine or scraping will smooth out the waves;
  • The contact area of the subfloor will increase dramatically;
  • you can make do with a smaller thickness of OSB.

But this is not always possible with thin existing flooring.

The upper layer of the underlayment made of OSB

Wood boards are excellent for the top layer of black floor, as they increase the performance of the structure:

  • provide an even base for the flooring;
  • increase spatial stiffness and strength of the foundation;
  • reduce labor and material intensity of the work.

Unlike floorboards, the self-tapping screws are screwed into the OSB boards strictly vertically. In the slope of the metiches can change geometry, warping of the material over time.

The main problems arise with the divergence of opposite walls (trapezoid instead of rectangular room shape). In this case, it is necessary to mark out the existing wooden floor in order to undercut only the boards of the first row:

  • along the long wall of the room is drawn axial line;
  • depending on the size of the boards parallel to it is made marking;
  • the edge of the sheet OSB, mating with the wall, is trimmed with a hand hacksaw or power tool;
  • the second and succeeding rows are placed along the marking without cutting, taking into account the offset of the transversal joints;
  • The last row is cut in a similar way to give the sheets a trapezoidal shape.

Thus, the structural material OSB is suitable for both the creation of the top layer of the black floor, and for the repair of the finishing floor of tongue and groove boards, if the dismantling of this lining for some reason is not expedient in the room. When choosing oriented chipboard reduces the labor intensity of work, the home craftsman is quite satisfied with the available arsenal of tools.

Choosing a board for the floor

Choosing the right OSB for a wooden floor is not possible without taking into account such an important factor as the company that produces it. Preference is usually given to products from Europe and Latin America, well proven in all aspects (including strength indicators). To this we should add the need to assess the advantages and disadvantages of the boards themselves.

Advantages and disadvantages

The indisputable advantages of unique products include:

  • environmental cleanliness of the material, the basis of which is natural wood;
  • resistance to temperature drops and mechanical deformations
  • Excellent indices of strength and plasticity of OSB flooring;
  • Easy processing and installation of the products themselves;
  • the homogeneity of the structure and the attractiveness of the appearance;
  • comparatively low cost.

This list can be completed by a perfectly flat surface of OSB, on which as the underlay may be mounted any finish coatings (including linoleum). The multilayer structure ensures good parameters of sound absorption, as well as additional insulation and waterproofing of the decking.

Their relative disadvantage or disadvantage is the presence of phenol components, which, according to recent data, are completely absent in the latest environmentally friendly developments.

Required thickness

When choosing the right boards for the floor, it is important to consider not only the strength characteristics. To obtain a reliable and durable coating, you should take into account their thickness, which is chosen on the basis of the following considerations:

  • When laying OSB on a rough concrete base is quite enough boards of 10-millimeter thickness.
  • When you intend to lay OSB on a wooden floor. preference should be given to blanks with a thickness of 15 to 25 millimeters.
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During roughing work on various construction sites OSB thickness for the floor ranges from 6 to 25 mm. Its specific value is chosen depending on the following factors:

Only if all factors are respected, it will be possible to achieve the desired result, guaranteeing the reliability of the construction of the floor base.

OSB flooring with your own hands

You can entrust the installation of floors to craftsmen, professional builders. They will make the floors quickly and qualitatively. But not cheap. You can save money by laying the floor yourself. over, the construction of the floor is not particularly difficult. It is only necessary to carefully study the technology of their laying and apply in practice the acquired knowledge correctly, in a certain sequence. Below we will tell you about how to make the floors from OSB by yourself, choose the material, what tools you need, about the work that must be done.

Laying OSB plates on the wooden and concrete flooring how to lay correctly

The subfloor is fast, high quality and inexpensive. this is the combination that most builders and their clients are trying to achieve. The easiest way to form such a flooring is to use OSB. Laying technology depends on the type of substrate and additional requirements for the finished floor.

  • High moisture resistance. The characteristics of this product do not depend on the influence of the atmosphere. Even when tested in conditions of immersion in water for a day, swelling was 18-26%, while the destruction was not detected, and the strength of the board retained;
  • Ease of use. As the product is lightweight, no additional lifting equipment is needed for installation. Absolutely everyone is able to perform the laying work;
  • Strength and durability. OSB boards have special properties, capable of withstanding even the most extreme conditions. In addition, thanks to the multilayered nature of the product, the material holds any kind of fastening elements (nail, screw, dowel and more);
  • Low cost. The product has an optimal price-quality ratio;
  • Wide range of applications. The boards are used for the lining of exterior and interior walls, the device base of the roof, the alignment of the flooring and more;
  • Eco-friendliness. The high quality board from a reliable manufacturer consists of 96 percent natural materials.

Example of laying OSB on the old wooden base

To understand this technology, the first thing to do is to inspect the old floor. Depending on whether you want to leave the existing flooring in place or dismantle it, the following procedure depends on.

Installing OSB on existing wooden flooring

If your old flooring does not creak, does not contain deep and wide pits, no fungus or mold, you can safely put wood boards on the existing flooring. However, the floor must be prepared for further work. Fill cracks and flaws with filler, trim off protruding parts, and check the work with a spirit level. Only after that can you start laying boards.

Attention! If you have the listed defects of the existing floor, it is not recommended to lay OSB boards until the defects are corrected, as the creaking from the installation of a new structure will not disappear. Fungus and mold will continue to rot and decay the wood. In such cases, it is necessary to dismantle the old coating, leaving the beams, and put a thicker slab.

After preparing the floor, start laying OSB. Start the process from the most even corner of the room. To ensure a clear fit of the material, you can trim the wood panel on one or more sides. Cut out the structures in sequence, carefully measuring the area of the room and the distance at which you want to cut slots and holes for communications, corners, etc.

The heads of the self-tapping screws should be recessed into the board by a few millimeters

It is necessary to take into account that during the operation of the material volumetric changes may occur. To prevent the formation of undulations, it is shown to leave dilatation gaps in the following size when installing the structure:

OSB should be fastened with self-tapping screws and nails 35-60 cm apart. The coverage will be of higher quality, if the material is fixed not only along the perimeter, but also along the diagonal of the product.

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