Have you ever wondered why the problem with housing has been solved in America for a long time? It's simple, they massively build prefabricated frame or panel houses, such buildings are cheap, and the time from “beginning to housewarming” is only two weeks. In a similar way, the problem with housing in cities was solved in our country, when panel houses were built in the 60s. But in those days, the state was not engaged in construction in the villages, no one used accelerated technologies for low-rise buildings. Now everyone takes care of their housing on their own, in connection with this, frame and panel houses have become so widespread.
For all operational characteristics, frame houses fully meet the most modern requirements. Except one. On TV, we are often shown the consequences of a tornado in the same America, many wooden structures are scattered around, entire cities are wiped off the face of the earth. And all because most of their houses are frame-type, such houses cannot withstand hurricane gusts of wind. But do not worry, we do not have and will not have a tornado, this drawback can be ignored.
Ways of sheathing frame houses
What is a frame house? A frame is assembled from wooden beams, either edged timber from pine and spruce is used, insulation is made, the internal and external surfaces of the walls are sheathed with various materials. For these purposes, drywall, plywood, boards, plastic panels and OSB boards can be used. Here we will stop on the last material (OSB boards). Let's talk about technology, you will get some practical advice on how to perform such work quickly and with minimal financial costs.
Choice of slabs
We recommend working with 12mm thick boards, but you can use thicker or thinner boards. Although we advise you to take our advice: thinner ones are a concern for strength, thicker ones will cost you dearly.
The slabs must be dry, for long-term storage it is necessary to use a canopy. Work should only be carried out in dry weather. The number of plates is determined based on the total area of the walls of the building; it is not very difficult to make calculations. However, it must be borne in mind that the amount of unproductive waste will always be at least 10%. The more complex the architectural characteristics of the house, the more waste there will be, keep this in mind when purchasing the material.
General sheathing rules
There are many different options for finishing frame houses, both interior and facade walls. We will consider only one of these options - sheathing of external facade walls with OSB boards. How you will sheathe the interior - does not make much difference.
Can be mounted in a vertical or horizontal position, leave a gap of 2÷3 mm between the plates. To facilitate the process of setting the gap, you can use a simple device. Find any plastic strip with a similar thickness and use it as a template, after fixing the slab, the strip is removed and used during the fixing of the next slab.
The distance between the stops of the slab should be 40 ÷ 60 cm. This must be borne in mind during the construction of the frame, it is better to use mineral or glass wool as insulation. Fasten the plates with spiral or ordinary nails, self-tapping screws and other hardware. The length is selected taking into account the thickness of the slab, while it should be borne in mind that the nail must enter the body of the timber to a depth of at least 40 mm. It is desirable that the caps of the fasteners have an increased diameter.
Nails should be driven ≈ 30 cm apart, at the joints of the sheets, nails are driven in at a distance of ≈ 15 centimeters. The distance from the edge of the board to the nail must be ≥ 1 cm.
Frame house cladding technology
Initial data - the foundation has already been completed, the lower strapping row has been laid, vertical racks have been mounted at the corners and perimeter of the frame house.
- We recommend starting the installation of the first OSB sheet from the corner of the house. In terms of level, fix it to the corner posts of the house, immediately fix the second sheet to the other side of the corner. During work, carefully check their position with a level. If you make a mistake on the first sheet of a few millimeters, then at the opposite corner your millimeters will turn into centimeters. Correcting such a mistake is very difficult. To fully guarantee the accuracy of the upholstery with sheets of walls, we advise you, as in many cases during construction work, to use strong ropes stretched along the walls. They will help you accurately maintain the parallelism of the sheet installation lines.
- Mount in a circle, leaving space for window and door openings. Do not forget that the sheet must be reinforced around the entire perimeter of the openings; in some cases, additional beams or special load-bearing racks will have to be installed for this purpose.
- Upholstery of the house with slabs from the corner greatly simplifies and speeds up the construction process - there is no need to install longitudinal braces. In the future, these cuttings still have to be removed - an extra waste of time and material. But you can’t do without temporary transverse braces, otherwise the frame will be too unstable.
- To facilitate the process of attaching the OSB () to the bottom harness, we advise you to fix a small bar at the place where two large sheets of OSB fit, after which you can fasten the sheet with screws or nails to vertical racks. If you have problems with horizontality, on some sheets you can “sacrifice” the gap, make it a little larger or completely eliminate it. If this defect is on 3-4 sheets, then you can not be afraid of any deformation due to linear expansion of OSB sheets.
- Work in a circle from bottom to top.
- Install interior load-bearing wall studs only when at least three house frame walls are assembled and sheathed.
Finishing sheets can be done in any way. But we would advise you to additionally protect them with plastic panels or siding - this will significantly increase the life of the entire building.
OSB sheets in a frame house allow you to decorate the outer walls of the house. Outside, OSB sheets are finished with either a ventilated facade, such as siding or plaster.
What thickness sheets to use for outdoor work
OSB sheets have an outer and an inner side. The outer side consists of coarser fibers - it should be screwed in outward.
What membrane is used to cut off moisture
Use a quality waterproof membrane. Better, one that is used under the roof
Groove for thermal expansion of sheets
Leave 3-5mm between sheets as space for expansion
How far to fasten the screws
How to cut the crate profile
Scissors for metal
MASTERMAX 3-ECO membranes
material three-layer waterproofing super-diffusion membrane (PP fleece) MASTERMAX 3 ECO - Masterplast application vapour-permeable underlayment roofing film, secondary protection against moisture and snow, placed directly on thermal insulation density, g/m2 115 g/m2 (±20 g) vapor permeability (Sd), m 0.05 max. pace. use, °C +70
What is expensive waterproofing material used for?
Over time, every material ages. This also applies to waterproofing membranes. To leave the water resistance of the walls of the house from LSTC at the proper level, you should use a high-quality moisture-proof membrane.
Required Tool
- Screwdrivers
- Self-tapping screws with pressure washer
- Steam waterproofing
- waterproofing membrane
- self-tapping screws for metal
What it is
OSB (Orient Strand Board or OSB) is an oriented strand board (OSB) in which each next layer of chips is laid across the previous layer. After that, the layers are glued together with waterproof resins and placed under a press at high temperature. Types of OSB
OSB boards (OSB) were created for use in the construction of low-rise wooden houses in the relatively warm and dry climates of the United States and Canada. This probably explains the fact that in the humid climate of Russia, moisture-resistant sheets of the OSB-3 class are widely used. OSB classification is based on their possible use in construction.
Depending on the production method, moisture resistance and strength, there are four types of OSB.
- OSB-1 - has low mechanical strength and low moisture resistance.
- OSB-2 - has high mechanical strength and low moisture resistance.
- OSB-3 - has high strength and is resistant to moisture.
- OSB-4 is a high-tech type, has increased strength and rigidity, very high moisture resistance.
In addition, OSB is divided according to the type of coating into lacquered and laminated, which are used under the formwork. And also according to the degree of processing - into polished and unpolished.
Imported OSBs are divided into European and North American, depending on what standard they were manufactured to. The American standard is more stringent. This applies to strength requirements, dimensional tolerances, and environmental compliance. However, the water resistance of North American OSB is noticeably inferior to European ones.
Story
OSB was first made in 1982 in North America at one of the woodworking factories. In the USSR, the appearance of OSB dates back to 1986, when a plant for their production was opened in Belarus.
Production technology
For the manufacture of OSB, flat chips up to 180 mm long and 6 to 40 mm wide are used. Chip layers are stacked in such a way that the inner layer is laid across the sheet, and the outer layers along the sheet. Usually OSB sheet consists of four layers, which achieves greater rigidity and reduces the ductility of the finished sheet. To increase the protective properties of the sheet, synthetic wax and a boric acid salt are added to the adhesive resin. After that, during the process of heat treatment at high temperature and subsequent hot pressing, the finished sheet is obtained from the chips. Properties
The main properties of the OSB sheet are strength, rigidity, low specific gravity, ease of processing.
OSB satisfies all the requirements for wood boards, but at the same time has the quality characteristics of wood. At the same time, OSB, unlike wood and plywood, is not subject to rotting, delamination and warping. In addition, they are not hygroscopic and are not affected by insects.
At present, thanks to a radical improvement in the quality of adhesive resins, it has been possible to establish the production of environmentally friendly OSB sheets.
Advantages of OSB board
- The obvious advantages include their resistance to moisture and increased strength, as well as a small specific gravity.
- OSB processing is not difficult. They are easily drilled, planed and sawn.
- The OSB sheet securely holds the fasteners. These indicators are more than twice as high as those of chipboard.
- Application The use of OSB is due to their properties.
- They are used for wall cladding, and with any kind of external coatings.
- They also make a continuous crate under the roof from OSB, regardless of its type.
- In addition, OSB is widely used for the assembly of subfloors and flooring, and is also used as supporting surfaces.
- Load-bearing structures are made from OSB sheets in wooden housing construction, as well as removable formwork in the production of concrete work.
- High-quality packaging and sandwich panels are produced from OSB.
OSB processing
- OSB is processed in the same way as a massive tree. In this case, it is desirable to use milling cutters, saws and drills with hard alloy nozzles. In this case, the feed rate should be somewhat lower than that used for processing solid wood.
- Sheets should be supported to avoid vibration during processing.
- It is possible to cut OSB both on stationary machines and with the help of hand tools.
- Plates, during processing, to reduce vibration, it is desirable to fix.
Fastening OSB occurs, in general, in the same way as fastening solid wood products, with screws, nails and staples. To increase the strength of the connection, ring and spiral nails are used. Smooth nails are not recommended.
When installing load-bearing structures, fasteners made of stainless materials should be used.
Since, with a change in humidity in the OSB, changes in volumetric characteristics may occur, safety gaps should be left between the OSB sheets, which will protect them from deformation.
Features of the use of OSB, OSB
OSB slab, according to technology, should be transported and stored in such a way as to avoid damage during installation. For storage of Osb, it is most convenient to provide a closed storage room with good ventilation. It is also possible to store Osb under a canopy so that they are not exposed to the risk of precipitation. In case of impossibility of storage, laying of Osb slabs according to the technology under a canopy, it is necessary to prepare for laying a flat horizontal surface in the form of a platform and ensure isolation from the ground. Wrap the pallet with a film, cover with a tarpaulin or in some other way protect it from moisture, while at the same time allowing air to enter the plate. Possible options for protection technology and pallet stacking are shown in the figures.
Osb floor installation technology
Osb with straight edges should be connected according to the technology on the floor logs, observing a temperature gap of at least 3 mm around the plate. When installing an Osb floor between walls or in the case of "floating floors", a gap of 12 mm must be left between the Osb and the wall according to the laying technology. The slabs must be laid on the floor with the main axis perpendicular to the joists. The connection of the short edges of Osb according to technology should always be on the logs. Long edges not laid on joists should have a tongue-and-groove profile, an appropriate support or connecting brace. If the room where the flooring is being laid does not have a roof, then during precipitation, drainage should be provided.
OSB or OSB (oriented strand board) is a relatively new building material that has become a successful alternative to plywood and chipboard. The role of OSB in frame construction is great, with the insulation of standard houses. Especially often, with the help of OSB, floor surfaces are formed and leveled. Today we will talk about how to do this correctly.
Types of OSB boards and their characteristics
OSB - boards consisting of several layers of wood chips pressed and glued with waterproof resins. Its gluing is carried out in 3 layers. In the outer layers, the chips are laid along the length of the panel, and inside - perpendicularly. This arrangement gives the OSB strength, allows you to firmly hold the fasteners.
The following types of OSB are used in construction:
- OSB-2 - panels with low moisture resistance. They are used only for interior work in dry rooms.
- OSB-3 is a versatile material. Withstands high humidity both indoors and outdoors. A large margin of safety allows it to be widely used in construction.
- OSB-4 - the most durable and moisture resistant plates. They are used to form load-bearing structures in conditions of high humidity.
For the construction and leveling of floors, OSB-3 sheets are usually used, which perfectly withstand the load from furniture, equipment, and the movement of people.
When leveling small floor defects, it is enough to use OSB boards with a thickness of 10 mm. Surfaces with significant bumps and potholes will require a material of 10-15 mm. If it is necessary to create a floor on logs, then the thickness of the OSB boards used should be at least 15-25 mm.
OSB boards are used as an even and solid base for various modern coatings - parquet, tile, linoleum, laminate, carpet. The main functions of oriented strand board are:
- Creating a floor surface. OSB is a popular material for creating a subfloor on logs. In this case, the flooring of the slabs can be carried out both on the upper side of the log and on the lower side.
- Surface leveling. Installing OSB on a wooden or concrete floor will help create a completely flat surface suitable for laying a finishing coat.
- Floor insulation. OSB board is 90% natural wood chips with high thermal insulation properties. Accordingly, the OSB floor does not allow heat to escape and keeps it indoors.
- Noise isolation. The multi-layer dense structure of the OSB reliably absorbs any kind of noise.
Consider several popular technologies for laying OSB on different bases.
Installation of OSB boards on a concrete floor (cement screed)
Let's start with the simplest situation - leveling the concrete base with OSB slabs. Work is carried out according to this scheme.
Debris is swept from the concrete base, dust is removed with a vacuum cleaner. The surface must be absolutely clean to ensure adhesion of the mounting adhesive. The base is covered with a primer. This also contributes to better adhesion of the adhesive to the base. In addition, the primer creates a dense film on the surface, which does not allow the screed to “dust” during operation.
OSB is laid out on the surface, if necessary, trimming is performed with an electric jigsaw or a circular saw. On the wrong side of the OSB, a rubber-based parquet adhesive is applied, using a notched trowel for uniform application. Glue the sheets to the concrete base.
Additionally, OSB is fixed with driven dowels. For guaranteed retention, the dowels are hammered around the perimeter every 20-30 cm. If the floor is even, the installation is carried out in a dry living room, then it is enough to fix the dowels at the corners of each slab (subject to the mandatory use of high-quality glue!).
When laying between the plates, expansion joints with a thickness of 3 mm are left. Along the perimeter of the room, between the OSB and the wall, the seam should be 12 mm. These gaps are necessary to compensate for temperature and humidity expansions (bulges) of the OSB during operation.
At the last stage of work, the OSB base is cleaned of dust and debris. The seams between the wall and the slabs are filled with mounting foam. Its drying time is 3-4 hours. Excess dry foam that protrudes beyond the surface is cut off with a sharp knife.
Installation of OSB boards on boardwalk
Laying OSB on an old wooden floor helps to level the surface and prepare it for the installation of the finish coat. Installation is carried out in this way:
- To begin with, with the help of a level or a rule, the localization of irregularities (bulges, depressions) of the boardwalk is determined.
- Boards that “walk” or rise too high above the general level are attracted to the joists with dowels, sinking them into the material. In some cases, to eliminate the creaking and unsteadiness of the boards, the floor has to be sorted out with the replacement (repair) of the lag.
- They clean the influxes of paint from the flooring, bloating and protrusions are washed with a grinder or emery cloth.
- OSB boards are laid out on the floor, with the seams of each next row shifted. Cross-shaped joints should not be! Dilatation gaps are provided (between the plates - 3 mm, along the perimeter of the walls - 12 mm).
- Holes are drilled in the plates. Their diameter should match the diameter of the wood screws that were selected to fix the OSB to the floor. Holes are drilled along the perimeter of the plates every 20-30 cm, countersinking is performed under the caps of the self-tapping screws.
- Self-tapping wood screws attract the OSB to the floor. The recommended length of self-tapping screws is at least 45 mm.
- If you want to make the floor more durable, mount the second layer of OSB. The seams of the overlying and underlying layers should be laid with an offset of 20-30 cm.
- Deformation gaps near the walls are filled with mounting foam, which is cut off after drying.
This completes the process.
Laying OSB on logs on a concrete base
In the presence of a concrete base (for example, floor slabs), the installation of a log and sheathing them with OSB sheets allows you to create a flat floor without the use of wet leveling screeds. And also to fit insulating, moisture and noise insulating materials into the structure.
Consider the technology of creating an OSB floor on logs on an existing concrete base. Logs (wooden bars) are fixed to the concrete floor with dowels or anchors.
The wider the distance between the lags, the thicker the OSB boards used. If the pitch is 40 mm, then the minimum OSB thickness is 15-18 mm, if the pitch is 50 cm - the thickness is 18-22 mm, if 60 cm - 22 mm or more.
Thanks to the lags, space is created between the OSB and the concrete floor. It can be put to good use by laying insulating material. For example, the floors of the first floors are often cold, so a heat insulator can be laid between the joists: mineral wool, polystyrene foam, XPS, etc. If there is a wet basement under the ceiling, the floor structure is supplemented with vapor barrier films or membranes.
OSB boards are laid across the log. The seams between adjacent plates (in width) should go strictly in the middle of the log. During installation, it is recommended to leave expansion gaps (3 mm - between the plates, 12 mm - between the OSB and the wall)
The sheets are fixed to the lags with self-tapping screws or nails (spiral, ring). Step of fasteners: along the perimeter of the sheets - 15 mm, on intermediate (additional) supports - 30 mm. Nails (or self-tapping screws) fixing the plates along the perimeter are placed at a distance of at least 1 cm from the edge (so that the OSB does not crack). Fasteners are selected so that their length is 2.5 times greater than the thickness of the plates used.
How to fasten OSB boards on logs in an ordinary city apartment, see the video:
Creating a subfloor from OSB on logs
Laying OSB on wooden joists is the easiest way to get a durable and reliable subfloor. This technology is especially appropriate with the existing columnar, pile, pile-screw foundation. Work order:
- Logs are mounted on the foundation. The step of the lag should correspond to the thickness of the OSB boards used (the larger the step, the greater the thickness).
- Perform a rough floor roll. To do this, retaining bars are nailed along the lag, OSB boards are laid and fixed on them. The surface facing the ground is covered with waterproofing preparations, for example, bituminous mastic.
- A layer of vapor barrier is laid on top of the OSB.
- Thermal insulation material is laid, for example, foam plastic, mineral wool boards, ecowool, etc.
- Close the insulation with another layer of OSB. Fastening is carried out in the same way as when laying OSB on logs on an existing concrete base (the technology is described in the previous paragraph).
At this point, the work process is considered completed.
OSB processing for different finishes
A strong, hard and even surface makes OSB a universal base for all modern floor finishes. How to cover the floor from OSB? Here are some popular solutions:
- Lacquer or paint. In this case, OSB boards will act as finishing floors, which will only require decorative finishing with paints and varnishes. OSB sheets do not require any additional preparation, it is enough to clean them of dust and apply 2-3 layers of varnish (paint).
- Roll materials - linoleum and carpet. When laying rolled materials, it is necessary to ensure that the joints between OSB boards are flush with the rest of the surface. It is desirable to remove all irregularities with sanding paper. Expansion gaps - fill with elastic sealant.
- Tile(ceramic, vinyl, quartz vinyl, rubber, etc.). In order for the tile to be held on the base of the OSB, it is necessary to ensure its immobility. For this, lags are placed more often than required by the thickness of the sheets. The step between the fastening elements is also reduced. The tiles are glued onto the OSB using a special adhesive suitable for the wood surface and the tile used.
- Laminate- topcoat, which is fixed in a "floating" way, without rigid fastening of the lamellas. This coating is quite rigid, so it is not necessary to prepare OSB for laying laminate. Minor irregularities that may be at the joints of the plates are leveled by the substrate.
What exactly to choose - it's up to you.
Using OSB makes it possible to inexpensively and quickly level an existing wood or concrete floor. And if necessary, create it from scratch on the logs. The OSB surface will not require expensive finishing, additional leveling, coating with moisture-resistant compounds. This is an excellent choice for those who want to create a quality floor with minimal effort.
Orientation of OSB boards OSB OSB Boards consist of three layers. Chips in separate layers are located crosswise. This structure provides a high level of:
- Size constancy;
- Fracture resistance (flexural strength);
- Shear strength inside the slab.
Since the OSB board consists of three layers, it has a longitudinal and transverse axis. The longitudinal axis coincides with the prevailing direction of the top layer chips. It is parallel to the direction of the inscriptions (markings) applied to the plate on the edge of the plate. On milled panels, the longitudinal axis is perpendicular to the markings on the panel surface. The strength and modulus of elasticity of the plate in bending along the longitudinal axis is 2 times greater than that of the transverse axis. Therefore, during installation, it is necessary to observe the correct orientation of the slab specified by the designer (especially in single-layer building structures).
2. Acclimatization of plates and protection against water and humidity OSB OSB OSB
Plate acclimatization
Before installation on the construction site, according to the recommendation http://cmknn.ru/osb-3-osb-3, it is necessary to acclimatize the plates min. 48 hours to equalize their moisture content with that of the environment at the application site.
Approximate values of board humidity:
- Installation conditions.
- Approximate material moisture content
- Premises with constant heating 6 - 9%.
- Premises with intermittent heating 9 - 10%.
- Room without heating 16-18%
OSB boards during their storage and use must be protected from water. After installation on the outside of the building, on the walls and roof, it must be covered with appropriate insulation to protect against adverse weather conditions. The edges of OSB 3 boards (especially at the edges) are exposed to high humidity, may swell moderately (in accordance with the norm). In this case, before installing the final elements (eg asphalt shingles on the roof), it is necessary to evenly sand the slab joints (to ensure an even surface).
To prevent damage to OSB boards, it is necessary to eliminate excessive moisture, which can be caused by:
- Using materials that are too damp or wet;
- Installation on non-dried objects built using "wet" processes;
- Errors during insulation work (water leakage into the building, improper installation of a vapor barrier, etc.);
- Insufficient weather protection (exterior walls and roof must be protected with appropriate insulation immediately after installation).
3. Cutting, milling, drilling OSB boards
The slabs can be processed in the usual way used for processing solid wood. It is best to use cutting tools and drills with a cutting part made of hard alloys. The feed rate depends on the tool being used. It is recommended to reduce the feed rate moderately compared to the feed rate used when processing solid wood. The slabs must be fixed in such a way that the slabs do not vibrate during processing. It is allowed to cut slabs with the use of hand power tools
4. Mounting plates
Fastening rules:
- The minimum diameter (section) of the staples should be 1.5 mm with a length of 50 mm;
- For OSB board, you can use nails as for solid wood, screws or staples.
- When mounting load-bearing structures, it is necessary to use connecting elements made of stainless materials (galvanized or stainless steel).
- Strengthening the strength of the connection can be achieved by using special nails; ring or spiral (the use of nails with a smooth core is not recommended.).
- The length of the connecting elements must be at least 2.5 times the thickness of the board to be attached, but in no case less than 50 mm; the distance from the connecting element to the edge of the slab must correspond to seven times the diameter of the connecting element (i.e. when using nails with a diameter of 3 mm - at least 20 mm);
- the maximum distance between nails driven into the edge of the slab should not exceed 150 mm;
- the maximum distance between nails hammered in the middle of the slab should not exceed 300 mm; plates with even edges are mounted on supports (ceiling frame, ceiling beam);
- fastening of OSB boards of small thickness must be started from the middle of their upper part and evenly continue fastening in the direction to the sides and down (to prevent swelling and deflection of the board).
5. Dilatation gaps (lat. dilatatio - expansion) OSB OSB OSB
- When installing the plates as a supporting structure of "floating" floors, it is necessary to leave a gap of about 15 mm wide when they are joined to the wall.
- When installing plates as wall cladding, it is necessary to leave a gap of about 10 mm wide when they are joined to the foundation;
- If the length of the surface on which the boards are mounted exceeds 12 m, it is necessary to leave expansion gaps between the boards with a width of 25 mm every 12 m.
- Since volumetric changes can occur in the boards (mainly due to changes in ambient humidity, which affects the material), it is necessary to leave expansion gaps between them, which prevent waviness or other undesirable phenomena on the boards. plates with even edges - it is necessary to leave gaps between them at least 3 mm wide when joining. plates with milled edges ("comb - groove").
- When docking, dilatation gaps are formed by themselves. Expansion gaps 3 mm wide must also be left when joining plates with other structures, for example, with a window frame, doors, etc.
6. Surface protection and paint coating on the OSB board
We recommend to carry out the so-called test painting, which can reveal the incompatibility of the paint with the substances contained in the board. When painting, follow the instructions and rules developed by the paint manufacturers. For interior surfaces to be painted, we recommend using sanded boards. To paint the surface of the boards, you can use the usual colorless or colored paints used for painting wood.
ATTENTION!!! - When painting or immediately after painting, chips may come out from the surface of the boards, and when water-based paints are used, chips may partially swell. Such occurrences are not grounds for complaint.
7. Application of OSB OSB OSB A1
- A1 Roof detail with prefabricated roofing
- A2 Roof detail with prefabricated wet environment
- B1 Roof detail with asphalt coating
- B2 Asphalt roof detail for wet environment
- C Detail of the external load-bearing wall
- D1 Detail of internal load-bearing wall
- D2 Detail of internal partition
- E1 Floor detail with "light" floating floor
- E2 Floor detail with "heavy" floating floor
Basic principles for the use of OSB boards in wooden structures and buildings
When designing and manufacturing reliable wooden structures with a long service life, it is necessary to follow the basic principles of wood protection. Without an appropriate solution of the components of the structure in terms of building heat engineering and checking the temperature and humidity inside the structure, it is impossible to guarantee the mechanical strength and stability of wooden structures, as well as their resistance to the destructive effects of biological factors. To ensure a long service life and reliability of new wooden structures and buildings, it is necessary to analyze all designed structures in terms of possible diffusion and condensation of water vapor or the temperature-humidity ratio, as well as the corresponding stable moisture content of the wood, for compliance with the requirements that establish environmental parameters for the use of OSB boards .
The main difference in the possible limitation of the influence of water vapor penetrating through the structure follows from the method of analyzing the properties of the vapor barrier layer. Vapor barrier layer of a building structure, which limits the penetration of water vapor from the environment into the building structure, due to the equalization of temperature and water vapor pressure in the indoor and outdoor environment. During this process, as a result of decreasing the temperature below a certain value, condensation of water vapor can occur. The resulting condensate can have a negative effect on the properties of the building structure or reduce its service life. Limiting the penetration of water vapor into the structure means limiting diffusion (penetration of water vapor caused by partial pressure) and moisture flow (penetration of water vapor caused by air current). In the specialized literature, one can find a classification of materials for a vapor barrier layer according to the equivalent diffusion thickness. The equivalent diffusion thickness Sd (m) determines the air gap, which provides the same resistance to water vapor as the corresponding layer of the building structure.
Note: The Sd value is not the diffusion resistance value of the structure layer, given in m/s-1). A significant increase in humidity in the outer layer compared to the calculated model at the site of material damage is caused by the spatial distribution of moisture and their unequal properties.
The difference in material properties can be caused by the following:
- violation of technological discipline
- poor-quality connection of certain types of materials and their contact with openings and surrounding structures
- compound aging
Humidity and OSB boards OSB-2
Carrier boards for use in dry environments (12% humidity resistance) OSB-3 Carrier boards for use in humid environments (24% humidity resistance) OSB boards are classified as OSB-2 and OSB-3 according to the standard.
Humidity class 1
It is characterized by moisture content in structural materials, which corresponds to a temperature of 20°C. and relative humidity of the ambient air, exceeding the value of 65% for no more than a few weeks a year. The average stable moisture content of most conifers does not exceed 12%.
Humidity class 2
It is characterized by the content of humidity in structural materials, which corresponds to a temperature of 20°C and a relative humidity of the ambient air exceeding 85% for no more than a few weeks a year. The average stable moisture content of most conifers does not exceed 20%.
Humidity class 3
It is characterized by climatic conditions that contribute to an increase in the moisture content of materials compared to humidity class 2.
General Recommended Principles for Designing Ceilings and Floors
9. Ceiling structures
OSB ceiling structures OSB OSB
Mounting: Mount plates with even edges on load-bearing beams with an expansion gap of 3 mm. Plates with tongue-and-groove edges must be glued together with glue (for example, polyurethane) to increase rigidity. Mount all plates in such a way that their longitudinal axis is perpendicular to the beams.
- Make sure that all faces perpendicular to the longitudinal axis lie on the beams. The width of the expansion gap along the perimeter of the walls must be at least 15 mm.
- fasteners: Nails 2.5 times the thickness of the slab, minimum 50 mm, with helix or grooves if possible. Screws with a length of 2.5 times the thickness of the board, at least 45 mm. (recommended screws with a minimum size of 4.2 x 45 mm). The maximum distance between nails is 150 mm at the joints of the boards, 300 mm at the plane of the board. Nails are driven in at a distance of at least 10 mm from the edge of the slab.
- Humidity Under the wooden ceilings of the first floor, located above the base, waterproofing is laid directly on the base to protect against moisture (film). During installation, protect the ceiling structures from possible exposure to rain. When the ceiling is open, holes must be made in it for the drainage of water.
- Recommended max. center distance between racks: min. the recommended plate thickness is 15 mm. 18 mm. 22 mm. Center distance between racks - 300 mm. 400 mm. 600 mm. 800 mm.
Note Center distances between uprights are indicative. Dimensioning is carried out taking into account the length of the slab and a certain exact value of the load on the slab.
10. Floor constructions on the bearing crate
The installation principles are the same as in the case of ceiling installation. When installing the boards, first lay a soundproof layer on the bearing bars (pillows) to absorb the sound of footsteps.
11. Designs of "floating" floors
Structures of "floating" floors OSB OSB OSB The floor structure consists of one OSB slab (OSB, OSB), "comb-groove" thickness. 18 - 22 mm or from two plates (recommended) thickness. 12 - 18 mm (min. 9 mm). The distribution surface of the floor can consist of a single OSB slab, for floors that do not have high requirements for dimensional stability, or in cases where no concentrated load is expected (in places above the tongue-and-groove joint). Otherwise, use a two- or multi-layer floor structure.
- The slabs are laid on sound insulation to absorb the sound of footsteps (rigid mineral wool or polystyrene mats intended for use in floor constructions).
- Separate layers of plates are laid in mutually perpendicular directions and connected by gluing along the surface or by screws.
- When using screws, we recommend connecting the boards in both directions or laying an intermediate layer between them (extruded microporous polyethylene or PSUL sealing tape) to prevent possible creaking. OSB-2 and OSB-3 are manufactured as structural boards with the appropriate permitted tolerances. Therefore, they can be used as a base for a classic parquet floor.
12. General recommended principles for the creation of structures for external and internal load-bearing walls
OSB boards OSB OSPOSB OSB OSB Installation
- OSB boards used for walls are mounted vertically or horizontally.
- When installing load-bearing walls, it is recommended to use boards that correspond in length to the height of the walls (to facilitate the determination of the required dimensions and the installation of boards).
- When installing plates horizontally, it is necessary to place strips of plates or stiffeners under all joints and free edges.
- The slabs can be fitted with a wooden frame structure on one or both sides.
- Plates are allowed to be mounted on the outer and inner sides of load-bearing walls.
Dilatation gaps
To prevent possible water absorption, the expansion gap between the frame and the concrete foundation must be at least 25 mm wide. Expansion gaps can be formed by installing the entire wooden structure on wedge pads, and filling the entire gap under the supporting wooden frame with cement mortar. If the frame is installed directly on the foundation, then it is necessary to provide its chemical protection and raise the plates above the foundation level to a height of at least 25 mm. An expansion gap of at least 3 mm wide must be left between the walls and along the perimeter of door and window openings.
fasteners Nails with a length of 2.5 times the thickness of the slab, at least 50 mm, if possible, with a spiral or grooves. Screws with a length of 2.5 times the thickness of the board, at least 45 mm (recommended screws with a minimum size of 4.2 x 45 mm).
Nails are hammered at a distance of at least 10 mm from the edge of the slab, in load-bearing walls - at a distance exceeding 7 times the diameter of the fastening material (at least 20 mm). - 625 mm.
Thermal and waterproofing boards
As an additional heat and sound insulation, it is recommended to use mineral wool from the front side. In this case, it is necessary to take into account the method of fastening this facade system. When using slabs for wall cladding on the outside, the diffusion resistance of the slab to the penetration of water vapor must be taken into account. On the other hand, slabs mounted on the inside of the wall can serve as a structural element with diffusion resistance (provided that the joints of the slabs and structural elements are sealed with appropriate insulating tape). When using tongue-and-groove plates, the tape can be replaced by gluing the tongue in the groove with glue (PUR, PVA). The junction of the lower edge of the wooden structure with the foundation must be covered with a protective waterproofing compound (for example, based on bitumen emulsions). Recommended max. center distance between individual fasteners (nails, screws) Plate thickness; 9 - 12 mm. 12 - 15 mm. 15 - 22 mm. At the edges of the plate; 100 mm. 125 mm. 150 mm. On the surface of the plate; 200 mm. 250 mm. 300 mm. For load-bearing walls, the center distance between fasteners is determined by static analysis. 13.
Mounting plates Before starting the installation of slabs on the roof structure, it is necessary to check the location of the rafters in the axes, whether they have a curvature and distinctive dimensions. Curved and other sized rafters adversely affect the properties and appearance of the roof. The slabs are connected in such a way that the faces perpendicular to the longitudinal axis lie on supports (rafters, slats, etc.) along their entire length. Therefore, it is recommended to choose the location of the rafters in modules with a span of 833 mm or 625 mm. In the case of a different or greater span length (> 833 mm), in order to improve the surface of the roof structure, it is necessary to choose the option with a longitudinal battens or boards 80 - 100 mm wide.
Using rails mounted with a pitch (in axes) of 417 or 625 mm, it is possible to achieve a reduction in the thickness of the slab (depending on the load). Plates with an even edge Between the plates there must be an expansion gap 3 mm wide. To level the roof surface and accelerate the temperature equalization of the slabs, it is recommended to strengthen the longitudinal edges of the slabs with steel H-shaped brackets.
Tongue-and-groove plates
To strengthen the roof structure and increase the diffusion resistance of the structural layer, glue the edges with glue (eg PUR, PVA). Fasteners Nails with a length of 2.5 times the thickness of the board, i.e. 50 - 75 mm, if possible, with a spiral or grooves, galvanized or stainless steel, with a diameter of at least 3 mm. Screws with a length of 2.5 times the thickness of the slab, but not less than 45 mm (recommended screws with a size of at least 4.2 x 45 mm). Nails are hammered at a distance exceeding 7 times the diameter of the fixing material, but not less than 20 mm.
Environmental influences (temperature and humidity)
The boards are used in the roof structure as a material with diffusion resistance. In rooms with normal air humidity of 50% (residential and office premises, etc.), they can be used in structures without a vapor barrier, provided that the expansion gaps of the boards are sealed with an appropriate insulating tape or gluing tongue-and-groove joints.
Environmental protection
Recommended max. center distance between individual posts and fasteners: Center distance between rafters; 600 mm. 800 mm. 1000 mm. Min. recommended plate thickness; 12 mm. 15 mm. 18 mm. Recommended distance between fasteners on the plane of the slab and the edge of the slab; 150 mm. Roof slope 40° or more - 150 Roof slope 30° - 40° - 200 Roof slope
Note. The dimensions are determined based on the adjusted value of the static load on the slabs. Boards that have been exposed to water (e.g. rain) must be dried before installation and roofing. The plate has a slippery smooth surface. Therefore, it is necessary to ensure the safety of installers when working on slabs mounted at an angle. When carrying out installation work on the roof, it is necessary to strictly observe the safety regulations and sanitary and hygienic standards established for work at height.
14. General principles of storage and warehousing of OSB boards (OSB, OSB)
OSB storage (OSB, OSB)
- For storage of plates it is most convenient to provide a closed storage room with good ventilation.
- It is also possible to store the slabs under a canopy in such a way that they are not exposed to the risk of atmospheric precipitation.
- If it is not possible to store under a canopy, it is necessary to prepare a flat horizontal surface and provide insulation from the ground with a layer of film, as well as wrap the pallet with film.
OSB storage OSB OSB OSB storage (OSB, OSB)
OSB boards (OSB, OSB) must be laid flat on a flat surface. OSB boards (OSB, OSB) should not be in contact with the ground to avoid possible contact with water. The ideal base is a plank or slatted pallet. In addition, OSB boards (OSB, OSB) can be carefully laid on wooden slats of the same thickness, the distance between the slats should not exceed 600 mm. Storage of OSB OSB OSB Incorrect laying can lead to deformation and damage of OSB boards (OSB, OSB). When placing several packs one above the other, the wooden slats must be in the same vertical plane. OSB boards (OSB, OSB) with limited space can be laid on the edge. In this case, the slabs must not come into contact with the ground and must be supported by a special rack. OSB OSB OSB Protection OSB (OSB, OSB) The top of the packs must be covered with a protective panel to prevent mechanical damage.
If the plates are outdoors, they must be protected with a moisture-proof coating. Protection during transportation OSB (OSB, OSB) During transportation, OSB boards must be protected from atmospheric precipitation. Humidity OSB (OSB, OSB) Like other wood-based boards, OSB boards (OSB, OSB) are hygroscopic and their dimensions change in response to changes in humidity. Changing the amount of moisture in OSB boards (OSB, OSB) can lead to changes in the size of the boards, and this can cause problems during the operation of the boards. A 1% change in moisture content will generally increase or decrease the length, width and thickness of different grades of OSB (OSB, OSB).
What is OSB, their advantages and disadvantages, types of oriented strand boards and the rules for their selection, technology for mounting panels on logs and a concrete base, features of decorative finishes.
Pros and cons of OSB flooring
Every year the demand for OSB boards is growing, which is not surprising, because the material has the following advantages:
- High level of panel strength. It is achieved due to the fact that in different layers of the board the chips are perpendicular. With the right choice of tile thickness, the structure will be able to withstand large power loads.
- Lightweight panels. The standard weight of a whole board is no more than 20 kilograms. Such material can be lifted independently, you do not have to hire a special team.
- The structure is resilient and flexible, which allows you to bend the boards without fear that they will break. This is very handy if you want to make OSB floors with rounded or other shapes, as well as when working with uneven surfaces.
- The panels have a high degree of moisture resistance. This effect is achieved through the treatment of boards with resins. When compared with other wooden building materials, this board will be less deformed when in contact with water or moisture.
- OSB is convenient and easy to work with. Panels can be installed using simple construction tools - saws, drills and screwdrivers. The cuts are even, no additional processing is required for them. On the OSB, various fasteners are well fixed - nails and self-tapping screws. Installation of plates will not take much time.
- The material has high performance in thermal insulation. Since OSB boards contain more than 90% natural wood chips, they perform the function of floor insulation. Therefore, such a floor covering will not allow heat to quickly evaporate and will maintain a stable temperature in the room.
- OSB provide a good level of sound insulation. The panels are multi-layered, thanks to which they absorb any noise well.
- Resistant to chemicals due to resin treatment.
- Particle boards are environmentally friendly. They are impregnated with special solutions that will not allow fungus or mold to form on the boards.
- OSB panels are budget and affordable.
- OSB flooring perfectly levels the surface. The slabs can be installed on a wooden or concrete floor, while creating an even surface on which the main finishing material can already be laid on top.
- They have a stylish color "under the tree", so that they do not require additional design processing.
In addition, an OSB subfloor may contain a synthetic substance such as phenol. But in the last few years, manufacturers have been actively solving this problem and are switching to the production of formaldehyde-free panels. Such material is considered absolutely safe for human health. On its packaging you will find the label "Eco" or "Green".
The main types of OSB for the floor
OSB is a panel consisting of three layers of wood chips, which are pressed and glued together with a waterproof resin during production. The direction of the chips inside the boards alternate: first along, then perpendicularly. Thanks to this arrangement, the plates are strong and hold the elements of the fastening system well.
In construction work, several types of OSB are used:
- OSB-2. Such plates have a low level of water resistance, so they are used only for interior decoration of dry rooms.
- OSB-3. These are universal boards. They are resistant to high humidity both indoors and outdoors. The material is very dense, therefore it is used in construction work of any complexity.
- OSB-4 panels. The most durable and moisture resistant type of plates. Often they are used to create structures in rooms with a high level of humidity.
Features of the choice of OSB boards for the floor
The most versatile material for flooring in a residential area is OSB-3. It is recommended to choose products manufactured by Western European manufacturers. Such panels meet European quality standards and have a high density.
The thickness of the OSB floor slab can be different, but in order for the panels to retain heat well, perform soundproofing functions, and also level the surface, it is recommended to choose products with a thickness of eight to ten millimeters. When mounting boards on logs, the recommended thickness of the panels is 16-19 mm. OSP-3 boards withstand various power loads and people's movements well.
To well level small defects in the flooring, it is enough to use a material ten millimeters thick. If the floor is with strong bumps and cracks, then 15-25 mm slabs will be required.
OSB is often used on the floor under linoleum, parquet, tile or laminate. This material serves as a high-quality and durable basis for a decorative coating.
Technology for mounting OSB boards on logs
The choice of material and floor design depends on the purpose of the room, its characteristics. As a rule, two main types of laying OSB boards are used - on logs and directly on a concrete screed.
Advantages and disadvantages of fastening OSB panels to logs
This version of the installation of the subfloor is quite simple, it can be done in a few days on your own. OSB panels are dense, resistant to crumbling, moisture resistant, not afraid of contact with biological and chemical substances and, most importantly, perfectly attached to the bars.
OSB joist floors are a great alternative to concrete screed. Such installation allows you to save money on building materials. In addition, the surface can be easily insulated, and the wiring of communications will not cause problems - they can simply be placed in the cracks between the wooden bars.
The advantages of laying OSB on logs include the fact that with their help the bases are perfectly leveled even with the sharpest drops themselves. It turns out a smooth surface, and the floor structure is not weighted. If some panels become unusable, they can be easily replaced.
Of the disadvantages of this installation method, it can only be noted that the whole structure turns out to be quite high, about 90-95 mm, and this will make the room lower.
Preparatory work before laying OSB on logs
The beginning of installation work is the preparation of the foundation. First of all, we inspect the floor for damage, cracks, chips, depressions, mold and mildew. If large defects are found, then they should be removed before laying the logs. Minor flaws can be left, since the height of the lags will hide them anyway.
Mold and fungus must be removed without fail. If this is not done, microorganisms will attack the logs, and eventually the OSB boards. This will lead to premature damage to the flooring. All debris from the floor surface should be removed.
Logs can be installed on the floor with a slope, but the maximum slope level should be 0.2%. To determine the angle, you must use a water level or a long building one. If too large slopes are found, they should be leveled with a self-levelling compound.
The procedure for installing lags on the floor
The dimensions of the bars for lags are always calculated according to individual measurements. In this case, the products must be of the same dimensions.
After they are prepared, proceed to the installation according to the following scheme:
- We install wooden beams around the entire perimeter of the room, fix them at the same distance from each other - 40 centimeters.
- The distance between the wall and the material should be no more than twenty centimeters.
- We fasten the logs to the base of the floor with bolts or self-tapping screws.
- The upper surfaces of the lags must be in a strictly horizontal plane. Their evenness should be periodically checked by the building level.
- If the room is damp enough, then the bars must be treated with protective agents against mold and fungus.
- If necessary, we put insulation in the gaps.
How to fix OSB on logs
For laying OSB panels on the floor, you will need construction tools such as a tape measure, a hammer, a water level, a jigsaw and a puncher. Also, for the installation process, prepare special fastening systems for woodworking and a nail puller.
Laying on the floor should be oriented strand boards with simple edges. Well, if they have grooves that will help fasten the panels together. To correctly calculate the required number of sheets, consider the fact that seven percent of the material will be lost during cutting.
Do-it-yourself OSB floors are easy to install according to the following instructions:
- The plates are laid across the lags.
- The seams between the panels should be minimal and go clearly in the center of the log. Between the OSB, you need to leave a distance of about two millimeters so that the floor does not deform over time and does not begin to creak.
- Between the OSB plate and the wall we leave a larger gap - 12 millimeters.
- We fix the panels to the beams by means of self-tapping screws or nails (ring, spiral).
- The step of the fasteners along the sheet should be about 15 millimeters. On additional supports - 30 millimeters.
- Fasteners that hold the plate around the perimeter are located at a distance of about 1 centimeter from the edge. This is necessary so that it does not crack.
- The length of self-tapping screws or nails should be 2.5 times greater than the thickness of the plate.
- The gaps formed between the walls and the rough floor covering must be filled with building foam or mineral wool.
Laying OSB panels on a concrete screed
The procedure for installing OSB boards on a concrete floor is preceded by a preparatory stage. From the base it is necessary to remove debris and dust. In order for the adhesive to adhere well, the surface must be clean. The base is covered with a primer. It will help the glue to better adhere to the panels, and will also prevent the screed from “dusting” during operation.
- The panels are laid out on the floor surface. If necessary, cut the OSB with a jigsaw or saw.
- Next, apply glue to the inside of the plate. To spread the product evenly over the surface, use a notched trowel.
- We glue the chipboards on the concrete base. Additionally, they can be fixed with the help of driven dowels, which should be placed every half a meter.
- Between each plate we leave an expansion joint, two millimeters thick.
- Between the walls in the room and wooden boards, the gap is no more than 13 mm. These seams are necessary so that during the operation of the coating no swelling occurs due to temperature and humidity changes.
- The last step in installing OSB boards on the floor is cleaning the panels from debris. We also carry out the sealing of all the formed seams with the help of mounting foam. It dries in three to four hours. Remove excess foam from the coating with a sharp knife.
Decorative flooring made of OSB boards
After the installation of OSB boards on the floor is completely completed, you can start finishing the flooring. If you plan to leave such a floor as the main one, then as an option, the surface can be completely varnished or painted, and skirting boards can be installed around the perimeter.
No additional preparation of OSB for painting is required. It is only necessary to clean the floor of dust and cover it with a couple of layers of varnish or paint. This can be done with a roller or a sprayer. Hard-to-reach places should be painted over with a brush.
There are panels that are more expensive, but they are already available with a glossy finish. Finishing such a coating will be very simple: just ennoble the perimeter of the room with a plinth - and that's it, the floor is ready for use.
If you are laying roll materials on top of the plates, for example, carpet or linoleum, then make sure that all the joints between the OSB panels are flush with the entire surface and do not protrude anywhere. Any small irregularities can be removed with sanding paper. Compensation gaps must be filled with elastic sealant.
For laying over OSB laminate, it is not necessary to prepare the panels. Small unevenness at the joints will be leveled by the substrate.
How to lay OSB on the floor - look at the video:
Installation of OSB boards is a way to inexpensively and efficiently level a concrete base. And if there is a need, then create a floor from scratch, fixing the panels on the logs. Such a coating does not need expensive finishing or impregnation with moisture-resistant solutions, and you can even lay it yourself.