How to lay plywood on the floor gaps. Plywood for flooring - which plywood is best for flooring in the house
Flooring made from plywood sheets makes the floor stronger and more resistant to deformation. This surface is an excellent basis for laminate, parquet boards, and linoleum. Laying plywood on wooden floor Helps conserve heat and reduces the amount of energy required for heating. In addition, the top layer of coating can, if desired, be changed after some time, leaving the base in place.
Laying laminate on plywood
Pressed wood boards successfully used for the construction of rough or finishing flooring. The material is inexpensive, easy to transport, and has obvious advantages:
- laying plywood under laminate on a wooden floor takes a little time;
- pressed veneer prevents rotting of the underside of the finishing coating due to good air exchange between the material and the wooden flooring;
- a flat surface extends the life of the floor covering;
- plywood sheets weigh little, but have sufficient strength, hardness, and are resistant to external influences;
- the canvas is flexible and does not break during installation;
- the material does not have a pronounced odor, is safe for health, and is suitable for arranging wooden floors in any premises, including children’s, medical, etc.;
- rough flooring retains heat well and absorbs noise;
- the canvas has big sizes, forms minimal amount joints during installation;
- factory grinding makes the surface of the material non-slip and prevents movement of materials placed on it;
- Can be used for flooring in the kitchen, bathroom, toilet due to its high moisture resistance.
Base for laminate Leveling a wooden floor with plywood also has some disadvantages:
- Instability to fire, rapid spread of flame. Plywood is compressed wood, so the level fire safety the leaf is not tall;
- The canvas is more expensive than chipboard, fiberboard;
- Laying plywood makes the wooden floor a few centimeters higher. This solution is not suitable for rooms with low ceiling.
Laying plywood with glue Types of plywood used for work
The material varies depending on the type of wood veneer used in production. Exist the following types canvases:
What kind of plywood to lay on a wooden floor? Exist different brands, suitable for certain types of work. In industrial construction, plywood of the FB and FOV brands is used. The FSF and FC categories are suitable for laying flooring in a residential area.
Canvas marked FC can be used to install a wooden floor under laminate in a nursery or bedroom. The material is impregnated with an adhesive composition that does not contain phenol. The fabric does not pose a risk to human health. Such plywood sheets are quite durable and have an average level of water resistance.
Plywood brand FSF FSF brand fabric is more resistant to water. The material is strong and durable regardless of temperature and humidity level. The canvas owes these properties to a special impregnation, which at the same time makes the plywood sheet toxic and unsuitable for laying flooring in a residential building.
The canvas is attached to the joists or directly to the floor surface. The first method requires more effort and time due to the need to build a foundation. Leveling a wooden floor with plywood without joists is done using glue. This method is suitable if the rough surface is flat, strong, and has no differences in height.
Laying on a wooden floor Installation on old wood flooring
Smooth, durable surface - good basis for laying plywood on a wooden floor. The advantage of this installation method is a slight rise in the surface after installation. Minimum thickness the sheet is 1.2 cm. The cut sheets are attached using special glue and self-tapping screws.
Tools and materials
Necessary tool For correct fastening plywood for a wooden floor you need the following tools and building materials:
- electric saw;
- roulette;
- level;
- marker;
- self-tapping screws;
- screwdriver;
- construction vacuum cleaner (a broom will do);
- roller;
- sander;
- plywood sheets;
- substrate;
- primer;
- glue.
Preliminary preparation
Layout of sheets Before you begin installation, you need to:
- Check the condition of the floor. It is necessary to strengthen loose elements, replace rotten, damp parts, and ventilate the room;
- Remove dust and dirt from the surface, prime the floor with a special compound for wooden surfaces. Then you need to dry the base for 16 hours;
- No alignment significant differences in height, up to 1 cm. To smooth out unevenness, you need adhesive tape and a special backing for plywood on a wooden floor. The joints between the strips of material are glued with adhesive tape;
- Place the sheets vertically to dry for 2-3 weeks at room temperature or slightly higher;
- Treat the dried fabric with an antiseptic solution;
- Ventilate building materials;
- Cover the plywood acrylic varnish in several layers. This treatment increases strength;
- Bring the plywood into the room two days before installation. The material is placed horizontally. This is necessary so that the canvas adapts to the microclimate of the room.
Marking and cutting
Marking by size Plywood is cut in such a way as to minimize the number of joints. The material is sawn taking into account gaps of 3-4 mm between sheets and 8-10 mm between the sheet and the wall. Indentations allow you to avoid swelling of the coating due to temperature fluctuations and increased humidity. The material tends to increase in size by several millimeters under the influence of the microclimate.
The plywood sheet is sawn with a jigsaw. It is necessary to carefully inspect the ends of the workpieces for delamination and sand the edges. It is convenient to cut the material into squares with sides of 50 or 60 cm. This helps to smooth the wooden surface and avoid installation defects. Each sawn square is numbered and indicated on the sheet layout diagram.
Fastening with self-tapping screws The correct installation of plywood on a wooden floor is done as follows:
- Spread the underlay on the floor, seal the joints with tape;
- Lay out the sheets to cut the material as rationally as possible. Plywood is placed taking into account gaps in case of expansion of the sheet under load or temperature fluctuations. The gaps between the sheets are 3-4 mm, from the wall along the edge of the sheet there should be 8-10 mm;
- Cut the elements with a jigsaw. For a spacious room, squares with a side of 50-60 cm are convenient. All parts are numbered, the location of the elements is fixed on the diagram;
- Drill the holes. Then follows a countersink drill bit larger diameter. When laying with glue, additional fastening is required. Holes are made at a distance of 2 cm from the edge. The distance between the fastening elements is from 15 to 20 cm;
- Apply plywood adhesive to the wood floor. The layer thickness should be 2-3 mm;
- Lay the canvases, starting from a niche, podium, ledge. Then place the sheets from the center to the edges, moving the squares like brickwork;
- Press the material down with a roller to ensure a secure grip;
- Secure the material with self-tapping screws to ensure greater reliability and prevent movement. The hats need to be thoroughly sunk. This will protect the bottom layer of the final coating from damage;
- Check the quality of the laid coating using a level.
Installation on joists Installation of the canvas on a pre-constructed structure is more labor-intensive and takes more time. This method is good because it does not require leveling the old coating. The logs themselves should be the same in height. The base is installed on the tree if its surface is strong and durable. The construction of the structure is not recommended in rooms with low ceilings, because the floor in this case rises by 8-10 cm.
Preparatory stage
Before laying plywood on a wooden floor, you should clean the previous covering, remove dust, large and small debris. It is necessary to inspect the cracks near the walls and between the floorboards and fill the largest of them silicone sealant. Assembly adhesive is suitable for this purpose. The material should be cut into squares, then each piece should be marked. A diagram of laying sheets is drawn on paper. The squares are arranged in bricks so that each next row is offset relative to the previous one.
Laying sheets along joists Logs are slats with a cross section of 40 by 15 mm and a length of 1.5-2 m. The guides are fixed on wooden boards using dowels or self-tapping screws. The logs are mounted so that their top forms a flat plane, and the slats serve as sheathing. The space between the guides is filled with material intended for heat and sound insulation. Cords and wires are hidden under the joists.
Wrote especially for you step by step instructions how to lay, starting from the choice of material and ending with the final sanding of the finished surface.
You need to mark, drill, and countersink holes on the sheets. Then comes the laying of the plywood floor itself on the wooden floor. Material is attached liquid nails or using self-tapping screws. In the second case, the caps should be thoroughly sunk into the canvas so that they cannot damage the bottom of the final coating.
Final processing
Floor surface scraping At the end of the installation, the joints are treated with fine-grained sandpaper. It copes with this task perfectly Sander with a special nozzle. This smoothes out minor irregularities and differences in height between adjacent sheets. Next, the floor surface is varnished in several layers.
Is alignment necessary?
Final flooring can be very demanding on the foundation. When installing, you need to create a perfectly flat surface. An old floor almost always requires adjustment in height, especially when it comes to installing the covering directly onto a subsurface without using a structure made of wooden joists.
Flat base Laminate flooring and parquet board. The increased demands of the final coating are explained by the presence of the system lock connections, which cannot perform their function when laid on an insufficiently flat surface. Changes in height lead to cracks and deformation of the floor. Places of loose joints subsequently become clogged with liquid and dirt.
Laying plywood on the floor, criteria for choosing material, varieties, advantages and disadvantages, installation technology.
The content of the article:
Laying plywood on the floor is a simple process, but you need to know how to cut the material correctly, how to fit the finished sheets and how to use them to level the surface. An equally important issue is the quality of plywood. To choose it correctly, you will need to understand the varieties and find out where each of them is used.
Main types of plywood for flooring
Wood-laminated board (chipboard) - construction material, consisting of several layers of veneer glued together. Each layer is laid perpendicular to the fibers of the previous one, which increases the strength of the material. An odd number of layers must be selected - minimum 3, maximum unlimited. The thickness of plywood is selected depending on where it will be laid, the expected load and the required strength.
The generally accepted division of plywood according to moisture resistance:
- FC (moisture resistant). The veneer layers are glued with a urea compound. The production technology allows the use of such plywood in residential premises, except for those where the humidity is higher than normal - bathrooms, kitchens, bathrooms.
- FSF (super moisture resistant). The veneer layers are glued together with poisonous phenol-formaldehyde resin glue. The material has high strength, wear resistance, and resistance to mechanical damage. This plywood is used mainly for exterior work. It is prohibited to use in baths and saunas.
- FBA (environmentally friendly). The veneer layers are glued with albumin casein glue. The use of such plywood is limited only to dry rooms, as it is susceptible to moisture.
- FB (moisture resistant). Impregnated with bakelite varnish. The scope of application is wide. Plywood does not deteriorate even in conditions of high humidity.
- BS. Plywood produced using bakelite glue on alcohol based. The material has increased flexibility, strength, is not affected by mold, and is resistant to moisture.
- BV. The veneer sheets are joined with water-soluble bakelite glue. Plywood is strong and flexible, but not moisture resistant.
When buying flooring material, you need to choose it correctly:
- Premium grade (marked E). The material has no external flaws. Used as a finishing coating, including for floors.
- First grade. There may be knots on the surface, but they do not exceed 10% of total area sheet, the length of the cracks is no more than 2 cm. This plywood is also used for finishing floor.
- Second grade. There are chips, knots, burrs, and cracks on the surface. The length of the cracks can reach 20 cm. Overall volume defects do not exceed 40%.
- Third grade. The gluing of the layers is high quality. Wormholes with a diameter of no more than 6 mm are allowed. The number of defects on the sheet is no more than 9. Plywood is used for leveling and creating a rough base for finishing the floor.
- Fourth, lowest grade. The gluing of the layers is of high quality, the diameter of the wormholes can reach 4.5 cm, the edge is uneven, there are many fused knots on the surface. For use on subfloors only.
Plywood can be laminated, sanded on both sides (Sh2), on one side (Sh1) and unsanded (NS). It is divided into two classes based on formaldehyde content (milligrams per 100 grams of dry weight) - markings E1 and E2. In class E1 level harmful substance is 10 mg per 100 g, in class E2 10 - 30 mg per 100 g of leaf dry weight. Plywood marked E1 is preferable for interior work.
Thus, the most the best option for the finished floor, birch plywood FBA-2E1Sh1 with a thickness of 12-16 mm is used. It is safe for humans, affordable and perfect for further installation of parquet, linoleum and laminate.
Important! Do not purchase third-grade plywood for flooring. Optimal combination prices and quality for flooring with second grade birch plywood.
Criteria for choosing plywood for the floor
Reasonable price, decent quality and environmental friendliness are the main characteristics of building materials that we always pay attention to. To finally decide on the question of which plywood to choose for the floor, you need to correctly assess your desires and capabilities.
When going to the store, pay attention to the following points:
- Glue. It is used to connect veneer sheets together. Urea and formaldehyde are hazardous to health. They slowly evaporate. When inhaled, you can get severe poisoning. Albumocasein and bakelite adhesives are safe for human health.
- Prices. If the price of a plywood sheet is suspiciously low, it is most likely a low-quality product from China. She has bad performance characteristics, “rugged” top layer and poor edge processing.
- Marking. Shows the resistance of the material to moisture and what impregnations the wood is treated with.
Advantages and disadvantages of plywood for flooring
Wood-laminated boards have 4 positive qualities:
- Strength/wear resistance. The original purpose of plywood is to strengthen weak spots on wooden floor. The veneer layers are glued perpendicular to each other, resulting in a durable surface. The thicker the plywood for the floor, the stronger it is.
- Low price. Plywood is made from veneer, whole pieces of wood are not used, and there is little waste during production. Therefore, the cost of the material is low.
- Versatility. Plywood, especially of small thickness, easily takes on rounded shapes. Using natural wood this is impossible. Using plywood, you can create rounded structures, and the finished surface will never crack.
- Easy to install. Plywood is easy to work with. It is easily cut with a jigsaw or a small hacksaw. Sawing can be carried out in any direction without fear of the appearance of knots and burrs. Such manipulations are impossible with wood.
The fear of moisture is due to plywood production technologies: water can get between the layers and seep deep into the sheet, destroying the adhesive joint. Bakelized plywood is used for the manufacture of yachts. She for a long time resists moisture, but is expensive. Therefore, it is irrational to use it for anything other than shipbuilding.
Technology for installing plywood on the floor
Plywood is laid on both concrete and wooden bases, according to the principle of brick bonding with offset, in order to avoid connecting the corners of four slabs at one point. Standard size the sheet is too large to lay it entirely, so it needs to be cut into four parts, obtaining small squares of 60 x 60 cm. In addition to basic ease of use, it is possible to increase the number of damping joints, which are necessary to compensate for deformations when the floor is exposed to heat and moisture .
Preparatory work before laying plywood
To lay the plywood you will need a few tools. This includes a screwdriver and self-tapping screws for attaching the material to the base, a level for checking evenness, a tape measure for marking and cutting, and a jigsaw for high-quality cutting.
Another important point- the surface on which marking and cutting will take place. It should be perfectly smooth and stable. Work with electric jigsaw requires precision movements. If the cutting table is unstable, you will not be able to cut the plywood correctly.
Leveling the floor with plywood begins with working on the rough base. This material is sensitive to the quality of the base, so you will definitely need a level for work. With its help, you need to check the base on which the plywood will be laid for evenness. If the slope is more than 1 cm per meter, you will have to resort to leveling.
If the floor is wooden and you do not plan to remove it, laying joists will be the solution. If plywood is to be laid on concrete, then you will have to work hard to level it “like an egg.” Before laying plywood, the room must be swept and vacuumed as thoroughly as possible.
Further steps if the base is wooden:
- Check the floor for strength, identify old rotten floorboards and replace them with new ones.
- Walk along the floor with a level. If the difference is up to 1 cm per meter, when laying plywood, use a system of underlays (small pieces of plywood with which you can achieve the desired height) under the sheets. If the difference is significant, it is best to remove the old coating completely and fill in a self-leveling concrete screed. True, it will take more than a month to wait until it completely dries and gains working strength.
- The second option for leveling a wooden base before laying plywood is a log system. It can also be used on a flat surface if you plan to lay wooden floors, laminate, carpet, or linoleum in the future.
The work is done like this:
- Clear concrete slab from debris and dust.
- Knock down any protruding bumps and fill in areas cement mortar.
- “Pound” the sinks with cement mortar. Let the floor dry, treat it with a deep-penetrating concrete primer to enhance adhesion between the subfloor and the future cement screed.
- Mark the floor into approximately equal squares. Use beacons for this. Pin them on gypsum mortar and set it to the desired level.
- Close the dry cement mixture water according to instructions. Use a drill with a mixer attachment for mixing.
- Place the solution in a square located in the far corner of the room, level it with a rule and bring it smooth with a trowel.
- When the solution has set, remove the beacon closest to the wall and fill a new square with the solution.
- Repeat the steps until the entire floor area is covered with a new screed.
- Wait 28 days until the new surface reaches working strength and is completely dry.
Trying and cutting plywood sheets for the floor
This stage also refers to preparatory work and consists of several mandatory steps:
- Measure the area of the room.
- When cutting, take into account the presence of damper gaps of 3-4 mm between sheets of material and one centimeter near the walls. If this is ignored, temperature changes and moisture ingress will lead to “swelling” of the base.
- Try on the plywood - lay it down without fastening the way it will be laid in the final version. Lay the sheets with vertical joints shifted according to the bricklaying method. The joints between them should be in the middle of the joist.
- After trying on, number the material.
Important! Be sure to check for defects; if the sheets are peeling, replace them.
Floating fixation of plywood to the base
There are two options for installing wood-laminated slabs on concrete - floating directly on the base and on joists.
Installation technology:
- Dust the leveled base.
- Place the cut and numbered plywood in a stack in the order of the sheets.
- Apply glue to the back side of the sheet (the glue should contain pine resin).
- Place it in the right (or left) far corner plywood coated with glue and press it to the floor.
- Using a hammer drill, drill holes in each corner of the glued board (the length of the dowel).
- Insert a dowel into the hole and hammer it in.
- Repeat the same with the remaining sheets.
- Seal the joints between the sheets with wood putty and cover them with mounting tape on top.
Fastening plywood to joists
This is the easiest way to level the base. Plywood with a thickness of 0.5-1 cm can be used as a log, or you need to purchase timber with a square section of 2 x 2 cm.
We attach the log system in the following sequence:
- Make markings on the floor for installing joists.
- Attach them along these markings using special wood glue and self-tapping screws. If there are gaps between the floor and the joists, fill them with pieces of plywood of suitable thickness, having previously coated both sides with glue.
- Make the sheathing. The dimensions of each cell must match the dimensions of the plywood sheets.
- Fill the empty spaces between the subfloor and the finished floor with insulation.
Watch a video about installing plywood on the floor:
Now you know everything about how to level a floor with plywood. Always use a level when working. Use it to level the rough base and install joists. Plywood - comfortable material for further finishing; in addition, it provides good additional thermal insulation and dampens some of the noise.
When making floors in residential and office buildings, a plywood base is often used. Laying plywood on joists to make a subfloor is a fairly reliable installation method. With this installation method, the advantages of plywood are more clearly demonstrated.
Laying plywood along the joists allows the subsequent production of the top layer of the floor of almost any type. This technology is applicable both when building a new house and when renovating a room. The method is very simple and can be done with your own hands.
Basic materials
The main materials are wooden joists and plywood. Typically, well-dried wood is used for logs. wooden beam. Recommended cross-sectional dimensions of timber:
- width -70 mm;
- height – 40 or 50 mm.
It is advisable to use a beam with a length of at least 2 m. The beam should not have deformations along its entire length. Before use, the timber must be kept for at least 10 days at room temperature, after which it is necessary to check that there is no deformation due to drying.
Plywood is used in the form of sheets. Standard sizes:
- 1525x1525 mm;
- 1220x2440 mm.
The sheet thickness must be at least 12 mm. For a two-layer coating, a 9 mm thick plywood sheet can be used. Sheets must be smooth and without damage. Residual deformation of sheets in any plane is not allowed.
Usually, cheap plywood of the “NSH” brand (unsanded) is used for the subfloor, and for parquet floors, the brand “Sh1” (sanded on one side) is used. The use of these grades of plywood is limited to a moisture content of no more than 60%. Where humidity is high or there is a high probability of floor flooding, it is recommended to use moisture-resistant plywood of the FK brand.
Step-by-step instructions: preparing the floor
Work begins with cleaning the floor from dirt, dust, household and construction waste, and remnants of previous coatings. To prevent the wooden elements from getting wet, a layer of roofing felt (roofing felt) or polyethylene film. The film is applied to the entire surface with an overlap of 15-20 cm. The joints of the film are secured with construction tape. If the film thickness is small, you can make the flooring in 2-3 layers. This type of flooring serves as waterproofing.
Before installing the logs, check the level of the floor for horizontalness. The installation sites for the beams are marked and parallel lines are drawn to the middle of future logs. Usually the timber is installed on pads. For them, plates made from pieces of boards or plywood are used. The recommended size of each such lining is: width – 100 mm, length – 200-250 mm, thickness – at least 25 mm. Wooden pads are attached to the floor with anchors on top of the waterproofing along the marked installation line of the joists. The level controls that the height of the floor along the lining is the same over the entire surface. If it is necessary to adjust the height, pieces of roofing felt or linoleum are added.
To prevent the formation of mold in the future, everything wooden parts and logs are treated with an antiseptic. For ease of floor installation, beacons are sometimes used. As beacons, you can use screws (self-tapping screws), which in terms of the height of the head correspond to the height of the installation of the log. Such beacons, screwed evenly over the floor surface, will help control their height and pressing force or the need for additional laying when installing the timber.
Installation of logs on the surface
The timber is laid according to the markings on the fixed linings. The logs are mounted parallel to the wall with windows, i.e. across the direction of entry into the room sunlight. The first lag is installed at a distance of 30-40 mm from the wall, and all subsequent ones - 40-50 cm from each other.
When specifying the distance between the logs, you must remember that the gap between the last beam and the rear wall should also be no more than 40 mm. The distance between the lags should be the same. The logs must be fixed parallel to each other strictly at the same height (along the surface). All logs are selected to have the same section size, except for the log located at front door. It is advisable to install this beam from a wider beam (at least 50 mm).
The logs are attached with screws to wooden pads, previously positioned and secured with anchors according to the markings. The heads of the screws should not protrude outward (it is advisable to have them recessed into the joist by 2-3 mm). The height of the logs must be strictly the same, so during installation the height is constantly monitored using beacons (if installed) or using a level. To increase the height, a roofing felt pad of the required thickness is placed under the joist.
The beacon allows you to determine the force with which the screw is screwed in, so the height of the log is adjusted.
To strengthen the lags, transverse bars (crossbars) are usually installed. Such bars are fastened across the beam in places where wooden pads are installed and are attached to them with screws.
For reliability, after installation the logs are all wooden elements coated with parquet or other similar glue. It is advisable to fill the volume between the joists with insulation and sound insulation. For this, mineral wool, expanded clay or expanded polystyrene (foam plastic) are usually used. Before backfilling, all communications are carried out (if necessary). It is also recommended to place a layer of parchment or bitumen paper on top of the lag.
Sometimes the timber is installed without the use of wooden supports. In this case, the lags are leveled by placing pieces of roofing felt. The joists are secured to the floor with anchors. The length of the anchor is selected 5-6 cm greater than the thickness of the bar.
Plywood laying process
For the convenience of laying plywood along the joists, it is advisable to cut a large sheet into squares or rectangles of a size convenient for high-quality work. The main requirement is that the size must be chosen taking into account that the edge of the sheet when fastening should be located in the middle of the beam. It is recommended that after cutting the plywood, lay it out completely on the floor. The sheets should be secured staggered, i.e. Joining more than two corners of sheets at one point is undesirable.
The points of their attachment to the joists are determined on the plywood sheets and markings are made. In the marked places, it is advisable to drill a hole for a screw and drill (countersink) a hole with a diameter equal to the diameter of the screw head. When attaching the plywood, this will allow the head to be recessed. The distance between the holes for the screw is selected within 20-30 cm, but taking into account that the number of fasteners on one sheet must be at least 8.
The prepared sheet of plywood is placed in a designated place and screwed to the joists and crossbars (if provided). Screws are selected with a length that is three times the thickness of the plywood. The joints of the sheets should be placed in the middle of the joists. The gap between the sheets is left within 2-3 mm. After laying the entire layer, the gap is sealed with mastic using a spatula.
Laying plywood is usually done in two layers.
When applying the second layer, you should avoid matching the joining seams in the layers.
The total thickness of plywood in both layers is selected within 24-25 mm. In each layer, the thickness of the plywood sheets should be the same, but it may differ in different layers. In the second layer, thinner sheets can be laid.
Tools and materials
When laying plywood, the following tools are required:
- electric drill;
- Bulgarian;
- screwdriver;
- jigsaw;
- hacksaw or wood saw;
- hammer;
- roulette;
- meter ruler.
Consumables:
- nails – 50, 70 mm;
- screws (self-tapping screws) – 35, 50, 75 mm;
- anchor bolts with a diameter of 10 mm;
- roofing felt or polyethylene film;
- construction tape;
- elastic mastic;
- parquet glue;
- antiseptic;
- parchment or bitumen paper.
Plywood over joists is a fairly lengthy and labor-intensive process, but it allows you to make a reliable floor that will last for many years. Happy renovation!
Floorboards are durable, environmentally friendly, and abrasion resistant. However, after several decades, the boards begin to creak, dry out, or rot from high humidity in the room. If you lay linoleum or carpet on an unprepared plank floor, or lay laminate or parquet, the surface will not be perfectly flat. All defects of the rough base will be visible through the final finishing coating, and in the case lock systems Installation will be impossible if uneven.
To make the floor high-quality and durable, you need to lay a backing under the flooring. For this purpose, sheets of plywood are suitable, which will hide all the unevenness and imperfections of the wooden floor.
Peculiarities
To choose plywood for leveling the floor, you need to understand the features and classification of the material on the market. Plywood varies in grade, thickness, moisture resistance and material of manufacture.
The main characteristics will help you choose the right sheets.
There are 4 types of plywood that can be distinguished visually:
- The fourth grade has defects on the surface, rough, there are holes from knots, since the lowest quality raw materials are used for production.
- The third grade is of better quality than the previous one and there is less defect on the surface.
- The second grade has minor cracks and is smooth.
- The highest quality and most expensive first grade is well polished, all sides are without defects.
When choosing a variety, they are guided by price and quality. For the construction of a subfloor, plywood of the second and third grades is suitable. According to the processing method, they are distinguished:
- Unsanded plywood.
- Sanded (one or both sides).
For installation on the floor, take one-sided sanded material, laying smooth side upstairs.
Plywood sheet is made from hardwood and coniferous species wood (usually pine and birch). Wood veneer bonded together with natural and synthetic resins. Upper layer can be treated with a varnished water-repellent composition.
Based on resistance to moisture in residential premises, the following brands are distinguished:
In bedrooms and others living rooms dream high humidity laying grades FK and FBA, made on the basis of urea and albumin casein glue. They are environmentally friendly and have average resistance to moisture.
The FSF brand is installed in the hallway and in the kitchen, where greater moisture resistance is required.
The thickness of the canvas is determined by the number of layers of veneer. An odd number of them are laid perpendicular to the previous one, creating a durable building material. For laying the subfloor, use plywood with a thickness of 10 mm and above.
Plywood lends itself well to fastening with self-tapping screws and does not crumble or crack.
An analogue of plywood in the construction market is OSB - oriented strand board. Such materials have similar properties, but differ only in production. For plywood, the raw material is wood veneer, and for OSB, wood chips are processed with natural resins.
OSB is divided into different categories:
- The first one is suitable for minimal load and dryness.
- The second is produced for low-traffic residential premises.
- The third is characterized by high moisture resistance and strength.
- The fourth is used in the construction of walls.
- Lacquered or laminated – coated protective layer varnish or laminate.
- Tongue-and-groove - has a connecting groove at the joints.
The best solution for the subfloor would be OSB 3, tongue-and-groove and easy to install. Such sheets are produced with a thickness from 0.5 cm to 4 cm.
Advantages and disadvantages
When it is difficult to decide which substrate is better: plywood or chipboard, you need to consider the advantages and disadvantages of each material. Plywood covering has the following advantages:
- Withstands heavy loads.
- Light weight.
- It is flexible and has high strength to bending and deformation.
- There is no foreign chemical smell.
- High leveling abilities.
- Easy to process and saw.
- Easy to use.
- Smooth beautiful outer surface.
- Retains heat in the room.
Advantages of using oriented strand boards:
- Affordable.
- They don't delaminate.
- Surface without defects.
- Various sizes.
- The panels are lightweight.
- Resistant to harmful insects.
But that's it wood materials have a common drawback - moisture has a great influence on them. Humidity will quickly destroy wood raw materials, so it is better to lay moisture-resistant types of coatings. The other negative side of moisture-resistant panels is environmental friendliness. They emit formaldehyde, which is harmful to health, but it is this that helps fight moisture.
Both leveling materials have high degree fire from an open fire, so before laying the material, you need to take care to increase the fire-retardant properties.
If you lay the flooring on joists, you lose up to 10 cm in the height of the room. This is not always acceptable in certain situations. To lay the sheets, it is necessary to make a clear calculation so that there is no waste and unnecessary rework. It is recommended to fasten these materials using self-tapping screws with an average pitch of 20 cm.
Such sheets tolerate fasteners well and are tightly attached.
The price differences between plywood and OSB of the same brand are not the most significant, but OSB is cheaper. In suitable and unpretentious conditions it is possible to lay OSB boards, but plywood is suitable for a durable, wear-resistant coating.
Materials and tools
Plywood and OSB are similar in laying technology. To cover the floor with wood sheets, use the same installation tools. The materials for fastening are also the same. In order to quickly and efficiently lay plywood sheets on a sub-plank floor, you need to stock up on basic construction equipment. In this work you will need:
- Level for measuring the evenness of the floor.
- Screwdriver or screwdrivers for screwing screws.
- Drill for drilling holes for dowels.
- Tape measure for measuring the required length.
- A jigsaw or hacksaw for sawing sheets of plywood to the required dimensions.
- Sanding attachment for drill or Grinder for sanding joints between sheets.
- Roller or paint brush for applying primer.
- A broom or vacuum cleaner for cleaning up debris.
- Spatula for applying glue.
- Hammer for nailing.
To increase the moisture-resistant and fire-retardant properties of the material, it is advisable to use special antipyretic compounds and primers.
It is better to lay plywood or OSB on water-dispersed adhesive bustilate or PVA. These brands are suitable for gluing wood surfaces. They are safe for health, odorless and dry within 24 hours. The glue is easily applied with a spatula or brush (depending on consistency).
You can fasten plywood sheets with screws and nails. If laying materials is carried out in an apartment, it is preferable to use self-tapping screws with dowels, since working with a drill and screwdriver is easier and quieter than using a hammer and nails.
Preparatory work
Before installing plywood on a wooden floor, basic preparatory work is carried out. First, the original rough timber base is assessed. Visually assess the condition of the floorboards, the presence of poorly fitted and creaky floorboards.
Check by construction level differences and surface unevenness.
Then the baseboards are dismantled. All loose boards must be additionally secured with nails or screws to the lower beam. Floorboards affected by fungus are replaced or cleaned, impregnated with an antifungal compound. Deformed and damaged boards need to be replaced. The protrusions on the surface are trimmed with a plane and sanded. Gaps and cracks are filled with sealant or glue.
After repairs, remove debris, sawdust and dust using a broom or vacuum cleaner. Unfinished plank floor is treated antiseptic. Rolled material can be laid under the plywood floor as noise insulation and insulation.
Penoplex or isolon of small thickness is suitable for the substrate. Connect the strips of the substrate to each other with construction tape.
The plywood is fastened after drying to avoid deformation. To do this, the material is brought into the room and left for 2-4 days. The optimal solution To protect against moisture and fire, both sides of the panel will be treated with a primer or acrylic varnish. The technology for laying wood sheets requires a distance of 1-1.5 cm from the wall between sheets of up to 0.5 cm.
This must be taken into account when cutting and laying plywood blanks on the floor.
To relieve stress from the material during operation and to make installation easier, the sheet is cut into 4 parts using a jigsaw. All parts are first placed and adjusted, a layout diagram is drawn and the workpieces are numbered. Sheets should be laid offset to reduce the number of joints and avoid crossing.
If you follow all the rules when laying plywood, it will serve as a high-quality, durable base for any floor covering. Finishing decorative material You can re-lay it, but the plywood base will remain the same.
Alignment methods
The leveling method depends on the levelness of the subfloor. Differences in height of more than 1.5 cm require plywood to be laid over joists. Minor irregularities are covered with plywood directly onto the wooden floor.
Boards with differences of less than 1 cm are leveled with supports in the right places. Thin squares, blocks of wood or plywood are used as support.
Laying plywood on the floor can be done with or without a backing. The lining roll is rolled out over the entire surface and secured with tape. Plywood material is spread on top in accordance with the diagram, the evenness is checked and secured with self-tapping screws. In this case, sheets with a thickness of 1 cm or more are needed.
Without the use of cushioning material it is applied glue method fastenings A small area of the room is covered with 2-3 mm of glue, starting from the corner. A sheet of plywood blank is placed on top and pressed tightly. Additionally, you can screw in several screws for better fixation. This method is used to install the remaining part of the room.
Laying birch plywood does not require special skills and can be done with your own hands.
When a sheet of plywood does not lie flat, bends, or there are slight differences in height with other pieces, supports are used. The support points are placed in poorly fitting places and are fixed through and through with self-tapping screws.
If on wooden base If the fiberboard is lying, then dismantling is carried out if the material is old, warped from moisture, crumbles and flakes at the edges. It is not recommended to lay fiberboard on the floor, since the sheets deteriorate from moisture and have poor leveling properties due to their small thickness.
To level out significant differences in height, logs are used. As logs, boards of the required length with a section of 3-5 cm by 7-10 cm or coniferous plywood slats of the same size are used. The location of the joists depends on the thickness of the plywood and the load during operation. Small thickness requires a smaller distance between the logs, starting from 40 cm. You should not use sheets less than 1.5 cm in height. The installation of the joists is designed in accordance with the layout of the plywood in the room, so that the joints are laid in the middle of the beam.
The horizontal installation of the logs is measured by water or laser level. The evenness of the entire floor depends on the accuracy of installation. The logs are attached with glue and screwed in place. Between them, bars are placed perpendicularly, creating a reliable sheathing on which plywood blanks are laid.
Often during repairs, dismantling the old wooden covering is not practical, but it is necessary to level the surface for further work. In this case, experts advise simply laying down sheets of plywood, thereby creating the necessary “platform”.
Laying plywood on a wooden floor
Pressed sheets are an excellent material for rough and primary work. They are inexpensive, easy to transport, easy to install and are good at eliminating small differences in floor level. Often they prefer to lay linoleum, parquet boards or laminate on plywood, since it has the following advantages:
- laying sheets significantly reduces time preparatory work before installing the final finishing floor covering;
- prevents rotting of the underside of floor coverings due to good ventilation between the material and the concrete screed;
- a floor lined with plywood prevents premature wear or deformation of linoleum or carpet, extending the life of the decorative coating;
- provides a smooth subfloor;
- plywood sheets are light, hard, durable, resistant to stress and abrasion;
- plywood is flexible enough and does not break during installation;
- has no pungent odor;
- has good sound and heat insulation properties;
- due to big size sheets, the number of joints is minimal;
- high-quality factory grinding prevents slipping of the sheet and materials placed on it.
Popular types of plywood used for renovation
Sheets produced by industry are classified according to various criteria:
- wood used;
- presence and method of impregnation;
- variety;
- number of layers;
- surface treatment;
- moisture resistance.
For repair work When the part of the structure made of plywood is hidden from view, it is recommended to use moisture-resistant plywood of grade II or III. The sheet must be at least 10 mm thick, but the recommended value is 14-22 mm. A thinner one will not cope with the load, and a too thick one will be inconvenient to work with.
The number of layers is not of fundamental importance. If possible, you should purchase sheets sanded on both sides.
- If possible, the plywood should be dried for 2-3 weeks before starting work. The sheets are dried vertically, at a temperature slightly above room temperature.
- After finishing the drying process, it would be useful to treat the plywood with an antiseptic and ventilate thoroughly.
48 hours before the start of work, the material must be brought into the room where it will be installed and laid horizontally. There are two ways to lay plywood.
Method 1. Installation on old wood flooring
When laying plywood on a wooden floor, there are many options for fixing the sheets:
- on self-tapping screws;
- on glue;
- for liquid nails.
Among adhesive compositions releases water-based adhesive, two-component composition, assembly adhesive and bustilate. However, fastening with self-tapping screws is preferable.
Materials and tools
To successfully install plywood sheets, you will need the following tools and materials:
- plywood sheets;
- jigsaw;
- level;
- roulette;
- marker;
- self-tapping screws;
- screwdriver;
- substrate;
- construction vacuum cleaner or broom.
You may also need a sanding machine, a roller and primer, glue and sealant.
Preliminary preparation and priming of the floor
Installation of plywood on wooden floors is carried out only if the height difference when checking the level is no more than 1 cm. In this case, you will also need a substrate to compensate for unevenness and tape, which will need to be used to glue the joints of the strips of material.
Inspect the condition of the floors. Strengthen creaking and loose floorboards, replace rotten and damp floorboards. Do not try to restore boards that have traces of mold, damage, or have been attacked by rodents. They definitely need to be removed and the room ventilated.
Use a broom to sweep away dust and dirt from the floors. If desired, go over the primer twice to wooden surfaces for better adhesion of materials. And dry the base for at least 16 hours.
Marking and cutting
Plywood sheets are sawn so that the number of joints is minimal, taking into account damping joints of 3-4 mm between sheets and 8-10 mm between plywood and the wall. This will help avoid swelling of the sheets, since during operation, under the influence of microclimate and fluctuations temperature conditions the workpiece will increase in area by several millimeters.
The cutting is done with a jigsaw, while the ends of the workpieces are carefully inspected for delaminations and sanded. On large areas for ease of installation, plywood can be cut into squares of 50x50 or 60x60 cm. This technique will help to more accurately level the surface and eliminate possible installation defects.
The sawn sheets are numbered, and similar to their numbers, a schematic arrangement of the workpieces is drawn on a wooden base.
Laying plywood
Installation of blanks has several features.
- If necessary, use the old one wood covering a backing is placed and the strips are glued together with tape.
- The holes for the self-tapping screws are drilled in advance and then countersunk with a drill of a slightly larger diameter.
- The screw heads are recessed into sheets of plywood.
- Laying plywood begins with niches, podiums, and ledges. Next, the sheets are arranged from the middle to the edges with a brick shift of the squares relative to each other.
- Cracks and gaps in the old flooring can be filled with glue, allowed to dry and peeled off.
Upon completion of installation, you should check the quality of the coating, remembering that the ideal gap between the level and the plywood is 2 mm, the maximum is 4 mm.
Method 2. Installation of plywood on joists
A more complex and labor-intensive method of laying plywood material along beams is justified if the height difference is more than 1 cm. Joists can be installed on an old wooden floor only if you are sure that everything is in order under it
Preparatory stage
Old flooring must be removed from dust and debris, paying sufficient attention to the gaps between the floorboards. The largest cracks can be filled with silicone sealant or assembly adhesive.
At this time, you should prepare the plywood - you need to saw the material, make markings on a piece of paper and number the squares, taking into account that they will be laid out in bricks.
Installation of logs and plywood sheets
According to the drawing, the plywood squares should be installed. Fastening can be done with liquid nails or self-tapping screws; in the latter case, the heads of the screws must be thoroughly recessed. The holes can be pre-marked and countersunk.
Final processing
Upon completion of laying the materials, the joints of the plywood sheets should be treated with fine-grained sandpaper, this will smooth out all the unevenness and differences of neighboring sheets. After sanding, the entire surface must be coated with several layers of varnish.
- If a laminate or parquet board will be installed on top of the plywood, then the thickness of the plywood should not be less than the finishing coating.
- Try not to allow 4 plywood sheets to touch at one point at once.
- The width of the log step should be 0.5 m from the side of the square.
- Plywood cannot be used in rooms with high humidity, even if it is a moisture-resistant grade of material.
- If non-moisture resistant plywood is used in the work, then prerequisite on next stage The work will involve laying a layer of waterproofing.
- The length of the screw should be at least 2.5-3 times the thickness of the plywood.
- When laying plywood on joists, after sealing the gaps between the boards, the base can be primed and a layer of heat and waterproofing can be applied, and only then the guides can be installed.
It is important to remember that defective plywood sheets cannot be used in the work, even if they are intended to be further covered with decorative materials.
Video - Laying plywood on a wooden floor
Video - How to lay plywood on a wooden floor