Cement-sand floor screed

Everyone knows what a floor screed is, but not everyone understands its necessity. This intermediate layer is the basis for the finishing floor, the quality of the surface coating depends on its quality. To level the foundations of stone, brick and concrete, when the level difference is 20 to 60 mm, a cement-sand screed is used. With its help, a foundation is created for the device of floor coverings of various types.

Benefits

It is worth noting the stability of the floor with a cement coating to the effects of water, mineral oils, organic solvents and other substances. Specific maximum pressure, which the cement-sand screed is able to withstand, is 600 N / cm.kv. Also, it can easily tolerate the average traffic intensity with rubber tires. As for impact resistance, it is characterized by the absence of any chips during the fall of objects with a weight of not more than three kilograms. Due to these properties, it can be used for screeds in offices, apartments, as well as in warehouses, commercial and industrial areas.

Composition

Cement-sand screed consists of the following ingredients:

- fine sand;

- cement (most often portland cement);

- modifiers (plasticizers, various shrinkage regulators);

- Special forces.

Thanks to fiber reinforcement, you can forget about the usual reinforcement of the floor with steel reinforcement. As for the modifying additives, the physical and chemical characteristics of the mixture change due to their use, and the frost resistance and plasticity of the screed increases.

The addition of plasticizers helps to reduce the water separation and delamination of the cement slurry, to reduce the rate of hydration, and also allows the cement to cure at the initial stage of curing, which results in a finer-grained and homogeneous structure. Cement-sand screed based on Portland cement can be used as a waterproofing and anti-corrosion layer. It will provide protection of reinforced concrete bases.

Thickness

The screed of the warm floor should be no thinner than 5 cm; If there are plasticizing additives in the composition, then at least 3 cm. When performing on a large area, it is necessary to use special units, the use of which contributes to a significant reduction in the expenditure of time and effort. There are several factors that affect the thickness of the screed:

- presence of an insulation layer;

- the degree of smoothness of the base;

- type of floor covering.

Thermal insulation

It is carried out by dense materials capable of carrying a load, such as mineral wool or expanded polystyrene. For application in screeds, the mineral wool density must be at least 150-170 kg / m3, and the density of expanded polystyrene is not less than 35. A variety of heat-insulating mound (foam glass, perlite, foam styrene), glass wool is used on floors that are performed on logs. You can use expanded clay, but, in comparison with polystyrene foam, it is less effective insulation, and to obtain the necessary coefficient, you need to make about 30 cm of backfill.