Flowing screed: guidebook

Flowing screed carries its name because it is a liquid mass that is pumped into a room - or several connected rooms at the same time. Compared to classic cement screed, this has important processing advantages, since the labor-intensive compaction, smoothing and triturating, as with cement screed, is eliminated. In addition, screed must not be transported in individual portions in the rooms, which must then be processed, but can be pumped with a screed machine equal to continuously via a conveyor system in the rooms.

A level balance is no longer necessary in the liquid screed, as it is self-leveling as a viscous liquid and automatically achieved in all areas because of the action of gravity, the same height and forms a flat surface. This leads to a much higher operating speed and thus usually also to lower costs. The load-bearing capacity of liquid screed is to be equated with that of cement screed; screed flooring has a particularly favorable effect on existing underfloor heating systems, since it offers the best possible heat transfer between the pipes and the floor.

Anhydrite liquid screed is standard

Most commonly used is so-called anhydrite liquid screed, usually calcium sulphate. Here, the binder is therefore no longer cement, but calcium sulfate. The grain sizes used in the screed sand are the same as in the conventional cement screed, namely 0-8 mm. Depending on which still different additives are mixed, and the CA screed usually made as liquid screed particularly liquid. However, anhydrite screed is not permitted in damp rooms and for use without flooring or in outdoor areas. It is true that cement screed can also be produced as a liquid screed, but this is not common and processing is usually problematic.

Advantages of liquid screed

In addition to the advantages already mentioned by the much faster installation and the elimination of compaction, smoothing and leveling is characterized in particular anhydrite screed by stress-free setting, he has very little shrinkage and swells usually very little. Unlike cement screed, floor screed can be laid completely without joints even on very large surfaces and reinforcement can be dispensed with. The drying time of liquid screed of calcium sulfate is significantly reduced compared to conventional cement screeds.

Where screed can be used - and where not

Flooring screed is not suitable for outdoor use and in damp rooms if - as usual - it is designed as a CA screed. Likewise, there is no way to use the screed itself as a floor covering. He always needs to be covered. Also problematic are different screed heights in individual rooms, which are usually not or only very expensive to produce with liquid screed. With underfloor heating, the screed made of calcium sulphate is the very first choice, with the heating usually being started about one week after installation.

Video Board: 17 Uheat Underfloor Heating Uponor Installation Guide