In this article we will talk about how to choose a quality coating for installing a subfloor without a lag with direct laying on a concrete surface. The topic of this article is not accidental, since the concrete foundation of the floor is used for a number of reasons both for arranging apartments in high-rise buildings and for constructing low-rise individual housing facilities.
But, the concrete surface in its pure form is not suitable for everyday use. Therefore, you want to lay the flooring, which will serve as a subfloor. In this case, the best solution would be laying plywood on a concrete floor. Let us consider in more detail the main points related to the conduct of these finishing works.
Features of the choice of flooring
Before laying the plywood on the concrete floor, we define the characteristic features of the material.
Plywood is made by gluing thin pressed sheets of wood material. Plates, regardless of the manufacturer's brand and modifications, have an odd number of layers. The number of layers depends on the purpose of the material and on the mechanical load that will be on the surface of the plywood.
For example, if there is a question: how to lay plywood on a concrete floor, you can use plates with a thickness of 16 mm, consisting of 11 layers or nine-layer plates with a thickness of 12 mm.
However, when choosing materials for laminate should be guided not only by thickness, but also moisture resistance. In this case, moisture resistance is the parameter that is determined by the type of glue used and the surface coating of the plate. According to the degree of water resistance of the plate are divided into the following types: FC, FOF and FSF.
Despite the fact that before laying the plywood on the concrete floor, steam or waterproofing is installed, it is better to choose plates with a high or at least medium degree of moisture resistance. In this case, the coating will not only be strong enough, but also durable.
Moisture resistance combined with environmental safety
Plates brand FSF are classified as materials with high moisture resistance. But their use is not recommended in rooms with excessive humidity. In the manufacture of these plates used adhesive compositions containing potentially hazardous phenol-formaldehyde compounds.
FC brand plates are medium in terms of moisture resistance of plywood, but in this case the sheets are glued together with glue based on non-toxic urea resins. For this reason, this material is suitable for use in any premises.
Another important point that should be considered before putting the plywood on the concrete floor is the raw material from which the slabs are made. Plywood is usually made from softwood and from birch veneer. Coniferous materials are preferable for flooring on concrete, as they are resistant to fungal infections, and therefore they are practically not moldy.
Plates of the FC brand are subdivided into 4 groups according to the degree of presence of external defects. But considering that plywood will subsequently be covered with carpet, linoleum or laminate, this classification is not so important. Moreover, by refusing to buy slabs with a minimal amount of defects in favor of purchasing less expensive materials, you can save a decent amount of money.
Features of mounting plywood on concrete
Before attaching the plywood to the concrete floor, make sure that the surface is completely dry. If we ignore this recommendation, sweat is formed under the floor covering due to the fact that excess moisture will not have access to the outside. As a result, the underside of plywood will melt, mold and collapse.
On average, it takes 1-1.5 months to completely dry the concrete screed. It is during this time that concrete gains optimum strength properties and becomes ready for further use. Completely dried screed covered with a layer of waterproofing, on top of which plywood plates are mounted.
Important: Under the floor covering you can hide various engineering communications. To this end, special grooves-grooves are made to the desired depth. Cutting reinforced concrete with diamond circles will help to cope with this task.
The installation instructions for plywood on concrete screeds are a series of work carried out in stages.
We list the main stages and tell about them in more detail:
- At the initial stage we carry out preparatory work.. Before you attach the plywood to the concrete floor, you must make sure that the surface is perfectly flat. Make it easy, enough to hold on a dry screed plaster rule.
- No matter how tangible the relief is, it needs to be leveled.. For leveling the hollows of the concrete floor, you can use ready-made spackling quick-drying mixtures, or you can use a cement-sand mortar prepared by yourself. In order to remove the protruding irregularities, diamond drilling of holes in the concrete is not required, since the flows of the dried mortar can be brought down with an ax.
Important: If the screed is new, it is advisable to treat it with a firming and dedusting primer for concrete products.
- On the prepared screed we lay out a special vapor barrier or a less expensive waterproof PVC film. Waterproofing is lined with stripes overlapping the next strip. We fasten the film with a wide tape.
- Next, we cut the plywood so that there is a gap of at least 1 cm between the plates and the walls.. The compensation gap is necessary so that the floor does not swell during use. The gap at the end of the installation can be covered with a plinth.
- We lay the plywood on the concrete floor so that the plates of one row are located with some displacement relative to the plates of another row.
- We fix the plywood to the concrete floor on the dowels. We drill holes for dowels and immediately drill out the sweats for caps. Dowel placed at a distance of 15-20 cm from each other.
- After the plywood is finally mounted recesses with caps, it is advisable to fill with wood putty.
As you could see, decorating the concrete floor with plywood is not so difficult. Meanwhile, the cost of doing this work independently is an order of magnitude lower than the cost of the services of professional installers. You will find more useful and informative information by watching the video in this article.