Laminate flooring requires preparation of the substrate. In addition to leveling concrete or other material, you need to think about the type of insulation and about creating a barrier to moisture, which can ruin the finishing wood board. Expanded polystyrene under the laminate solves these two problems and, in addition, is a kind of damper, reducing the load on the coating when walking.
What types of polymer are
On an industrial scale, three main technologies for the manufacture of foam sheets are known to obtain a product that is different in performance:
- method of non-pressurized form production
- use of special pressing equipment;
- receiving material in the extruder installation.
Any of the methods allows you to obtain a high-quality product designed to perform specific tasks of thermal insulation.
Non-pressurized polymer product
Under pressureless means expanded polystyrene, consisting of granules of the same diameter, tightly connected to each other under the influence of a thermal process. The density of the structure determines the strength of the product and ranges from 50 to 15 kg per cubic meter. The product is marked with the abbreviation PSB with numbers at the end indicating hardness. The product can be used as insulation for walls and roofs of buildings, various metal containers and as polystyrene foam for laminated floors.
High-quality plastic is easy to distinguish from low-quality plastic by breaking the sheet and checking the diameter of the grains - grains of different sizes indicate a fake.
Pressed polystyrene foam
PS is a product that is manufactured on pressing equipment by compaction of latex grades of raw materials using blowing agents. The structure of such plastic consists of closed cells. The main characteristics of the polymer structure:
- lack of electrical conductivity;
- low water absorption;
- retention of heat;
- blocking the passage of sound waves;
- unsuitability for the development of pathogenic flora.
The press polymer structure can be used in radio engineering, since it is transparent for radio waves to pass through.
Extruded material
In the manufacture of an extruded polymer structure (EPS), the raw material is melted in an extruder and then filled into a mold. The hardened mass has uniform cells and is almost completely waterproof. In addition, the performance in terms of mechanical stress is much higher than that of any other similar polymers. The product can be used for any insulation purposes, including as a substrate for expanded polystyrene laminate.
There are fire-resistant EPS grades made with the addition of fire retardants to the structure.
Production of sheets of extruded polymer
The process of obtaining a sheet of polystyrene substrate undergoes the following technological stages:
- The granules are mixed with a dye, an illuminator and fire retardants (if necessary).
- The granules are subjected to foaming, followed by aging for a certain time.
- The raw material is placed in an extruder, where it is heated and sintered.
- Through the nozzle of the heating box, the viscous mass is fed to a special pulling device.
- The resulting web is subjected to cooling in natural conditions or forcibly.
- This is followed by the process of stabilizing and grinding the surface.
- In the last step, the expanded polystyrene foam for the backing is cut into sheets and packaged.
The grade of the material obtained depends on the amount and type of additives that are added to the main composition at the first stage of the technological process.
Types of underlays for flooring
Not every polystyrene plate is suitable as insulation under the laminate. There are several types of this product designed specifically for this purpose. Their difference between themselves is in performance and in the thickness of the working layer. The ends of the joints are straight and with special grooves obtained by milling. In this way, the processed edges allow tightly matching the joints, avoiding gaps.
On sale you can find plastic in the form of rolls or single sheets.
2mm material
This type of polystyrene foam substrate has a density of about 40 kilograms per cubic meter. It is permissible to use such a thickness in the underfloor heating system, provided that the sheets have special perforations for the unhindered penetration of warm air to the floor surface. The disadvantage of the material is the impossibility of leveling the base under the laminate due to its small thickness, which must be compensated for by a more thorough preparation of the concrete screed.
Substrate in three millimeters
In terms of performance, the polymer has a higher level of density and durability. It is capable of withstanding a load of 45 kilograms per cubic meter. Installation specialists note the material's superior ability to level uneven subfloors. On the market, a three-millimeter polystyrene foam substrate can be found in a roll version and in the form of an accordion made of sheets.
Five-millimeter insulation
Sheet polystyrene foam on the floor for a 5 mm laminate has higher thermal insulation indicators than a similar 3 mm, by about 2%. In addition, it is able to effectively smooth out small irregularities on concrete and other substrates.
In order to avoid the accumulation of moisture directly under the insulation, it is recommended to pre-cover the concrete screed with a layer of vapor barrier.
Laying technology
The main condition for organizing the substrate is that the joint between sheets or rolls of polymer does not coincide with the joint of laminate or parquet boards. This is achieved by laying the insulation at an angle to the finish coating by about 45 degrees. The rest of the technology boils down to the following stages:
- Dirt and fine particles of debris are removed from the concrete surface.
- The screed is covered with a layer of vapor barrier.
- The polymer structure is laid in a checkerboard pattern.
In order not to trample the surface, you can lay the insulation in parts on the width of two strips of the board.
How to choose a manufacturer
A high-quality polystyrene foam substrate for work on the improvement of the floor surface can be selected based on the following considerations:
- The polymer manufacturer must be well known to consumers.
- A wide range of products, several grades of extrusion polymer structure, should be presented on the market under a specific brand.
- Upon request, for each type of product, a factory manager or a retail dealer is obliged to provide a certificate of conformity and a full package of documents.
Ultimately, in addition to high performance, the insulation must be safe for human health.
