Screed is the base for flooring. Its application is dictated by the need to level the floor surface before the finish. Also, the screed is intended to give the base a predetermined angle of inclination and mask various engineering communications. In addition, it gives the surface the necessary degree of rigidity and regulates its heat absorption. The screed can be laid directly on the base of the floor surface, as well as on various auxiliary layers. For example, for heat or sound insulation.
The most common is cement screed as the cheapest and most reliable way to level the base surface of the floor. The basis for this type of screed are Portland cement (a hydraulic cementitious type of cement mixture based on calcium silicates) and aluminate cements. As a filler, as a rule, a sand component or gravel is used.
The cement screed must have a thickness of at least thirty millimeters, otherwise there is a high risk of it peeling off the surface. The period of complete drying of this type of base for flooring is about twenty-eight days. But in the end, a perfectly smooth and very durable surface is obtained.
The cement screed device has some of its specific features. To prevent further cracking and peeling, the hardening of such a screed should occur in conditions of high humidity. For this purpose, a raw screed for up to seven days is covered with a plastic film, after removing which it is recommended to fill the surface with wet sawdust and regularly pour water over a seven-day period. The cement screed, to the device of which this approach is applied, after complete drying will have excellent performance and durability.
The upper boundary of the finished base surface must be below the floor level by the thickness of the intended flooring. The cement screed itself is laid on special parallel beacon rails, which are designed to provide a perfectly smooth surface. The interval between the rails should be approximately one meter. The cement slurry prepared in advance is laid evenly between the slats in a uniform layer. After laying, the beacons are carefully removed, and the vacant space is filled with a solution and leveled.
Another way to level the floor is with a dry cement screed. It is not yet so widespread, although it is cleaner, faster and less labor intensive. The principle of dry bulk floor has been applied for a long time. But recently, in the light of the emergence of new, relatively cheap materials, this technology has become increasingly attractive and in demand.
The principle of the device of this type of screed provides for the addition of polypropylene fiber to the cement mortar, which, evenly distributed in the mixture, reinforces it throughout the volume, which significantly reduces microplastic shrinkage and prevents the formation of cracks in the hardening process.
Such a screed has many advantages and advantages, among which one can note the speed of the work, its relatively low complexity, very quick drying and minimal shrinkage.