Self-leveling floors delight the eye with their colorful and modern look. It can be a shame when, after a certain time, cracks appear on the floor, which negate all its aesthetics. To the question of why the self-leveling floor is cracking, there can be no unequivocal answer. The reasons for the appearance of cracks can be both violations in the production technology and violations of the rules of operation.
Shrinkage of cement
Leveling the floor when pouring the screed is done using beacons and reinforcing mesh. The cement mortar poured between the beacons shrinks over time and imperceptible depressions appear on the surface of the screed. The amount of shrinkage is determined by the concentration of water in the solution during pouring.
An increased water content not only increases shrinkage, but also reduces the strength of the screed.
The self-leveling polymer floor should be applied to a well-dried and maximally leveled cement-containing floor. In order to check the floor for dryness (floor humidity should not exceed 5%), it is enough to lay a piece of film on its surface and leave it for a day. If after a day there are no drops under the film, and the floor does not visually become wet, then you can proceed to the flooring of the polymer bulk coating. To check the evenness of the floor, a two-meter wire is used. The floor is considered leveled if at a distance of 2 meters in different directions the surface differences do not exceed 2 mm, in the most extreme case - 3 mm.
Incorrect installation of beacons and grid
When installing beacons, the use of gypsum is not allowed, which, after drying, forms cracks at the boundaries of the connection with cement. Poor-quality material (sand concrete, cement, gypsum) used for pouring the screed, failure to meet the technological deadlines, also lead to the formation of multiple cracks on its surface after drying.
The reinforcing mesh should not be located at the base, but in the screed itself. A damper tape should be installed along the perimeter of the floor to compensate for the thermal expansion of the polymer layer. A common mistake is to install a concrete screed on a wooden floor.
buoyancy
Floor bubbling occurs due to the delamination of the top layer from the base due to the lack of waterproofing or high humidity of the base during pouring. Bubble is eliminated by removing defective areas, treating with a special primer and pouring a new layer.
Cracks and holes in the subfloor
Cracks and pits in the base of the floor appear due to violations in the process of priming the surface of the concrete screed. Increased humidity and porosity of the base, the wrong choice of primer, its savings in the process of work - these are the main causes of cracking. The elimination of such defects is achieved by expanding the crack to the base and filling it with a new mortar and mixture.
Incorrect use of the floor
During the operation of the floor and its regular cleaning, it is necessary to use special care products. The use of common household detergents can cause cracks to appear on the surface of the polymer coating. Do not leave puddles and wet spots on the floor surface, they must be removed in a timely manner with a dry cloth.
If, as a result of unprofessional installation or improper operation of the polymer coating, it swells and, accordingly, cracks, or a significant part of the coating is broken by cracks, then this part will have to be removed to the “live” coating and a patch should be applied. The patch is made according to the above instructions for repairing cracks in a polymer floor using polymer self-leveling floors.
With the formation of numerous small and large cracks, the appearance of the so-called "grid of cracks", the entire coating must be refilled.
