Air anhydrite screed - how does that work?

Anhydrite screed should dry as quickly and evenly as possible. The right heating and ventilation is decisive for this. How to do it right, what to look for, and what obligations you meet as a builder, read in this post.

Drying of screed

The drying times are very different for the individual types of screed. Anhydrite screed usually has a considerably shorter drying time than cement screed, but also needs a much lower residual moisture content for the ready-to-use layer of calcium sulphate screed.

The drying of screed can also be accelerated in different ways:

  • by condensate drying
  • Condensation drying in connection with fan
  • by sufficient air exchange (proper ventilation)
  • dry heating (is very detailed in underfloor heating anyway)

In many cases, a condensate drying is too expensive or not feasible. Proper ventilation is usually the method of choice, to shorten the drying of the screed noticeably and to run more evenly. This is definitely recommended.

Proper ventilation

Proper ventilation accelerates and harmonizes every drying process on the screed. Important are the following things:

  • adequate ventilation
  • not too much airing
  • no entry of additional moisture
  • regular airing
  • no drafts

Optimal for drying is a regular air change several times a day. It should always shock aired become:

1. Open the windows wide
2. no Create a draft!
3. After ventilation, the windows again shut down!

Windows that are constantly tilting do not provide an air exchange. This may even be counterproductive.

Should be ventilated about 2 - 3 times a day. That is enough for a sufficient air change. The cold air then in the room can absorb more moisture than the warm air, which forms after some time - thus the screed dries faster.

The duration of ventilation should not exceed 10 - 15 minutes. This period of time is sufficient for the forced ventilation in order to bring about a sufficient exchange of air.

If possible, do not ventilate when there is high humidity outside (eg on rainy days). In this way, you may be putting more moisture into the building than you are draining, and you may even worsen the drying result.

Tips & Tricks

The first 24 hours after installing the screed you are allowed to Not Ventilate. This time takes the screed to tie off. Of course, if condensation dryers are used, the windows must remain permanently closed during the operation of the devices.

Video Board: Flowing Screed