Screed is the basic base for flooring. Its use is dictated by the need to level the floor surface before finishing. Also, the screed is intended to give the base a given 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 both directly on the base of the floor surface, and on various auxiliary layers. For example, for heat or sound insulation.
Cement screed is now the most widely used as the cheapest and most reliable way to level the underlying floor surface. The basis for this type of screed is Portland cement (a hydraulic binder 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 be at least thirty millimeters thick,Otherwise, there is a high risk of peeling off the surface. The term for complete drying of this type of base for flooring is about twenty-eight days. But the result is a perfectly flat and very durable surface.
The cement screed device has some of its own specific features. To prevent further cracking and peeling, the hardening of such a screed must occur in conditions of high humidity. To this end, the wet screed is covered with a plastic film for up to seven days, after which it is recommended to cover the surface with wet sawdust and regularly water it for a seven-day period. Cement screed, to the device of which this approach is applied, after complete drying, will have excellent performance and durability.
The upper limit 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 lighthouse rails, which are designed to provide a perfectly flat surface. The interval between the rails should be approximately one meter. The cement mortar prepared in advance is laid in a uniform layer between the slats. After laying, the beacons are carefully removed, and the vacated space is filled with mortar and leveled.
Another way to level the floor surface is dry cement screed. It is not yet as widespread, although it is cleaner, faster and lesslaborious. The principle of a dry bulk floor has been used for a long time. But recently, in light of the emergence of new, relatively cheap materials, this technology is becoming more attractive and in demand.
The principle of the device of this type of screed provides for the addition of polypropylene fibers 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 during the hardening process.
Such a screed has many advantages and disadvantages, among which we can note the speed of work, its relatively low labor intensity, very fast drying and minimal shrinkage.
