The dry times of screed

Depending on the circumstances, the drying times of screeds can often be significantly different. In addition to the type of screed used and the construction method, many other factors such as structural conditions, humidity, room humidity and temperature play an important role here. The frequently specified default values ​​can also be significantly exceeded in practice in unfavorable conditions. In case of doubt, the actual drying condition of the screed itself always decides.

Important terms for drying

You have to make a fundamental distinction between accessibility and readiness for accessibility. Most screeds, including cement screed, can be walked on after just a few days, but cement screed can often only be ready after three to four weeks. The complete dehydration takes even longer. Other types of screed sometimes have much shorter times to maturity. However, it is also decisive for the maturity of the covering which coating is to be applied to the screed, since different types of documents also require a different physical strength of the screed in each case. In the case of natural stone and ceramic coverings, the screed must, above all, be stable against deformation, while the application of parquet or linoleum must rather pay attention to the moisture problem. Each type of screed has different properties for certain residual moisture, which must be taken into account here. Furthermore, it depends on whether it is a heated or unheated screed layer, and whether there is the possibility of frequent air exchange in the room.

Too rapid drying can cause cracking

Too rapid drying of the screed is usually also problematic, since the screed here chemically does not cure completely, but only partially. When applying the flooring, it may then come through the topping mortar to a moisture absorption of too quickly dried screed - here threaten then deformation and sometimes cracking.

Fast screeds often have shorter drying times

Using special additives, a screed can also be brought to a faster drying - in this case, this is harmless by the additives and causes no cracking or deformation during later application of the topping. The additives can either be added separately to an "ordinary" screed, or the quick screed is offered as a complete ready mix. Please note, however, that the rules for residual moisture, which otherwise apply to this type of screed, are no longer applicable, and any change in the additives will result in particular chemical and physical properties. Here then only the information of the respective manufacturer apply.

Residual moisture measurement

The residual moisture of a screed can also be measured - namely with a so-called calcium carbide measuring device or CM measuring device. A small sample of the screed mixed with calcium carbide is shaken here and the resulting pressure of the chemical reaction can be measured on a pressure gauge and converted into the unit CM%.

Video Board: ninja screeding dry concrete in Real time