- Features of working with material
- How a plank floor should be arranged
- Dry preparation method
- Screed preparation
- Adhesive selection
- Laying porcelain stoneware
From time to time we share with readers very specific installation instructions and today this is the case. This time we will talk about laying porcelain stoneware on a wooden floor and the main ways to ensure a long service life of such a coating.
Features of working with material
Porcelain stoneware is a dense, incompressible material that is practically incapable of elastic linear deformation. Unlike ceramic tiles, which are able to somehow “accompany” the vibrations of the subfloor due to their own porosity and sufficient joint width, porcelain stoneware retains absolute rigidity. Without a monolithic, immovable base, it simply tears through the body of the tiles.
On the other hand, porcelain stoneware is intended for use in areas with very high throughput and has no other advantages over tiles. Therefore, laying porcelain stoneware on a wooden base should not be a simple whim. Preparation of a wooden subfloor will be difficult and costly, respectively, the purpose of the coating should fully justify it.
If you do not take into account the complex preparation technology, then there will be no special difficulties with the installation of porcelain stoneware. Naturally, you need a quality cutting tool: either the simplest electric or a quality manual tile cutter with a well-oiled break function. Well, we will consider the features of the choice of glue and the installation process a little later..
How a plank floor should be arranged
The system of a wooden floor, prepared for laying porcelain stoneware, must have a number of strength characteristics, which could otherwise be considered excessive. The lag system should ensure absolute immobility, exclude even the minimal possibility of warping and shrinkage during temperature and humidity changes. It is also necessary to achieve high durability so that the life of the floor system is equivalent to the service life of the coating..
The required rigidity is achieved, first of all, by a fairly frequent step of installing the floor log. As a first approximation, the center-to-center distance between the logs should not be more than 20 times the thickness of the boards used for the rough flooring, and the thickness of the logs themselves should be 2–3 times greater than that of the flooring. The stability of the foundation and the building as a whole, as well as the type of wood used, and other conditions, make their own adjustments..
It is recommended to use glued beams for logs – the opposite direction of fibers in adjacent glued segments compensates for most of the manifestations of shrinkage. If a board placed on an edge with a thickness-to-height ratio of more than 1: 2 is used as a log, the logs must be fastened together with spacers of the same section with the same installation step. In adjacent rows, it is necessary to make a break in half the installation step, thus it is most simple to fix the jumpers with self-tapping screws or dowels, having previously drilled holes in the logs.
The flooring is performed with a grooved board without gluing and filling joints. You can also use an edged board, but in this case it is necessary to strengthen the joints from sagging with wooden dowels with a thickness of at least 1/4 of the thickness of the flooring. The pins are driven in in increments of 30-40 cm, here it is very important to evenly divide the depth of driving in both directions.
It is very important to minimize the effect of high humidity and temperature differences on a wooden structure, to exclude damage to wood by harmful microorganisms. In addition to the obligatory treatment with antiseptics, it is necessary to arrange the protection of the floor from water vapor and condensation, corresponding to the used insulation scheme. For safety net, the space between the logs can be covered with hygroscopic materials, for example, a mixture of sand, sawdust and slaked lime.
Dry preparation method
No matter how strong the base of a wooden floor may seem, it does not have a sufficiently high deflection strength, which for laying porcelain stoneware should not exceed 0.5 mm / m. Therefore, additional preparation is arranged on top of the subfloor and, by the way, a dry screed is not applicable in this case, no matter how hard the GVL sellers try to prove the opposite.
Dry preparation is the simplest and fastest method, it also requires a bit more investment in the purchase of materials. The essence of the technology is simple – the rough flooring is sanded or cycled with the leveling of the plane differences to a value of no more than 1 mm / m. Then the floor is covered with two layers of sheet materials, the task of which is to additionally fasten and level the elements of the subfloor, as well as to damp all subsequent manifestations of shrinkage.
The most suitable materials for strengthening the floor are plywood with a thickness of 8 mm in each layer, moisture-resistant gypsum fiber board with a thickness of 12 mm or magnesite plates with a thickness of 10 mm. Combinations of these materials can be used with stronger and stiffer materials in the top layer. Do not use drywall and OSB classes 1 and 2, their linear extensions are too pronounced.
Additional flooring is laid with a gap between rows and overlapping joints in different layers, each of which is fastened separately with self-tapping screws at least 2 points per 1 dm2. Such frequent fastening is really necessary, in addition, you need to take into account the width and order of laying the sub-floor boards. Sizing or other additional bonding between the layers is usually not required. At the joints between the slabs, along the perimeter of the room and in the places of passage of communications, it is necessary to leave gaps to compensate for expansions in the general order of 0.5-0.7 mm for each meter of the size of the room in the plan.
The device of a preparatory screed gives a great guarantee of success, but it is not always possible due to the difficulty of delivering a large volume of bulk materials to the upper floors. In addition, this method of preparation eats up the height of the room much more: 60–80 mm versus 20–25 mm.
Before pouring the screed, it is necessary to thoroughly waterproof the floor. The easiest way to do this is with a plastic wrap, which is spread with a fold on the walls about 20-25 cm and is attached to them with tape. The expansion of the screed is compensated for by means of a foam tape made of polyethylene foam, the thickness of which is at least 0.2% of the room size.
The screed for porcelain stoneware must be reinforced without fail. The easiest way to do this is to make a steel reinforcing mesh with a mesh of 100×100 mm and a bar thickness of 4.5 mm with a protective concrete layer of at least 15 mm. When using nylon or vinyl-carbon reinforcement, it is advisable to arrange it in two layers: the lower one is stretched on self-tapping screws screwed into the boardwalk, and the upper one is laid before the second stage of pouring with a self-leveling mixture.
The adhesive mixture for laying porcelain stoneware is characterized by a high content of a plastic polymer binder that can compensate for the residual linear expansion of the base. At the same time, the quality of the glue with the dry method of preparation should be higher than when laying over a reinforced screed..
On the preparatory screed, porcelain stoneware can be laid on a general-purpose tile adhesive – Ceresit CM-11 or CT-117, if the porcelain stoneware format exceeds 600×600 mm. You can also use the compositions of the manufacturers “Profit” or “Moment” similar in properties..
Laying on a layer of dry preparation requires the use of specialized highly plastic mixtures “Litokol” or Knauf Flex. The same compositions should be used if porcelain stoneware is laid on top of the underfloor heating system or there is an insulating underlay made of polyurethane foam or EPSP under the screed.
Laying porcelain stoneware
Before covering the floor, the surface requires a mandatory priming. For the screed, “Concrete-contact” is used, dry preparation can be processed with film-forming compounds that limit moisture absorption.
The adhesive should be applied to the substrate and not to the tiles, using a comb trowel with a tooth height approximately equal to the thickness of the facing material, but not less than half of it. Seamless installation is not recommended, even if the wooden floor is prepared with a screed – a minimum seam of 1 mm will be sufficient. Please note that in both cases, the quality of floor preparation for laying is very high, which means that a minimum of effort is required to level porcelain stoneware..
Grouting of porcelain stoneware can be done with tile glue or the simplest joint filling mixture, if you want to match the color of the joints to the tone of the coating. In this case, crumbling and spilling of the filler of the seams is very likely, but this will only be on the hand, if the room is dirty, the seams are irretrievably dirty and require periodic replacement. If you need to ensure the durability of the grout, use plastic compounds containing latex or white acrylic sealant.