Piece floor coverings are quite sensitive to the quality of the rough foundation. Laminate flooring is no exception. The increased requirements are due to the fact that in the presence of serious irregularities, the fastening system of the parts between each other is damaged when exposed to the floor load. To avoid this, plywood is laid under the laminate on a rough wooden floor in the presence of height differences and gaps between the boards on it.
Material selection
Laying rough plywood under a laminate on a wooden floor has a very important function, therefore, the choice of material should be taken responsibly. First of all, it is worth deciding on the variety, of which there are three sheets. The first is characterized by increased requirements for the outer surface and attractive appearance. The cost of such sheets is higher than lower grades. Laying plywood as a rough coating on a wooden floor under a laminate does not impose requirements on appearance, therefore it will be more rational to focus on materials of the second or third grade. This will save the repair budget.
The thickness of the flooring plays an important role, since the strength of the sheets and their ability to withstand the load depends on it. Laying plywood on a wooden floor under the finishing laminate involves the elimination of quite serious irregularities, so the support of the sheets can not be called continuous. The minimum thickness is 10 mm, but this is an acceptable value. The calculation of the optimal depends on the expected load on the floor, the severity of the bumps and the distance between the points of support. Recommended thickness is between 14-22 mm.
Laying plywood sheets on a wooden floor under a laminate is recommended with the use of polished material on both sides. This will ensure high quality grip flooring with the rest of the elements of the pie floor.
The choice of installation technology
Plywood as a rough floor under a laminate can be installed in two ways:
- without intermediate supports;
- with intermediate supports.
In the first case, fixing to the board flooring is performed on glue and self-tapping screws. The second option involves the use of two types of supports. Here it is possible to install point elements called scaffolds, and bars-logs. Using lag allows you to provide a more reliable foundation, but the first method is preferable in terms of saving material.
Without the installation of intermediate support points, it is possible to lay plywood under the laminate on the floor at elevation differences of not more than 1 cm. It is precisely such irregularities that can be fixed by sheets fixed to adhesive structures.
If it is required to correct irregularities of more than 1 cm, then the installation is carried out using a log or cobs. It is important to remember that the gaps between the boards, cracks or areas where there are no flooring elements should not exceed 5 cm in width. For more serious problems, it is better to sort out the rough flooring to prevent problems during operation.
Glue laying
The fastening of the sheets can be performed both on adhesive compositions and on liquid nails. To ensure additional fixation, self-tapping screws are used. As adhesives used two-component, water-based. You can use mounting glue or bustilate.
The work is performed in the following order:
- Checking the evenness of the base, cleaning it from dirt and dust, degreasing.
- The next step may be the priming of the surface. It is necessary that the adhesive solution most effectively connect the sheets and flooring of wood.
- After completion of the preparatory work, they begin cutting sheets of material. This is necessary in order to rationally spend raw materials and ensure high accuracy of installation. The sheets are laid out so that they cover the entire room (if necessary, cut with an electric jigsaw), while leaving a gap between the elements of 2-4 mm. This gap is called a damper seam, it prevents the appearance of waves on the surface with increasing humidity and temperature or after expansion of the sheets under load. This seam is required. Also, a deformation gap is provided between the flooring and the walls. Here it should be 8-10 mm. It is this layout that will ensure the most effective alignment.
- Unfolded items must be numbered. Then they are removed from a horizontal surface. Numbering is necessary so as not to make a mistake during installation and to complete it without temporary hitch.
- Having removed the sheets from the floor, holes are drilled in them for self-tapping screws. Using larger drills in diameter, these holes for fasteners are countersinked. The location of the fasteners is chosen so that they are located at a distance of at least 2 cm from the edge of the sheet. In this case, the pitch of the screws is taken within 15-20 cm.
- Having completed the preparation, you can begin the main work. Installation begins with niches, ledges or podiums. First, glue must be applied to the base. The layer should not exceed 2-3 mm. The sheet is installed in the design position and pressed to the surface. Next, go to the next element.
- You can start installing the screws only after the adhesive solution has dried. The fastener elements are installed in the prepared holes and screwed.
Important! When laying out sheets, you must observe the dressing. This means that each subsequent row is shifted relative to the previous one. The offset is taken at least 10 cm, but it is better to make it larger, for example, by half the flooring element.
Lagging
Most often, lags are used as intermediate supports. They allow you to simplify the installation of the frame under plywood, since the number of operations and measurements is reduced. Preparation of the base is carried out in the same way as in the previous case. The complexity of the work increases, but it becomes possible to eliminate serious differences without removing the boards of the wooden flooring.
After cutting the sheets, they begin to mount the logs. For their manufacture, boards with a section of 15 by 40 mm are used. The step is selected at the stage of development of drawings or sketches and depends on:
- sheet thicknesses;
- the width of the sheets (since their joint should be located on the lag).
If a material with a thickness of 14-16 mm is selected, then a lag step of 30-40 cm will be required. When using a material of 18-22 mm, the intermediate supports are laid more sparsely, at a distance of 50 cm from each other. Fastening the lag to the wooden flooring is carried out on self-tapping screws, when installing sheets of the rough floor, you can use fastening with self-tapping screws or glue.