Anhydrite screed aftercare

When pouring anhydrite screed, it is essential that for the first 24 hours the area remains free from frost and any other extreme temperatures, draughts and direct sunlight.

Anhydrite screed will typically dry at 1mm per day up to 40mm then 0.5mm per day thereafter, however thicker screeds will take longer.

If the purpose of the anhydrite liquid screed is for an underfloor heating covering, then the screeds traditional drying time can potentially be reduced by up to 60% by utilising the UFH system to force dry the screed. It is recommended that this process be done slowly to not shock the screed and cause imperfections. We would recommend starting the UFH temperature at 20C and holding at this level for the first 4 days. Then gradually bring about 5C incremental increases every 24 hours thereafter. This should continue up to a maximum of 50C and then held for 5 days before 5C increments are decreased every 24 hours until you reach 25C.

Always ensure there is enough ventilation to the area via an open window or dehumidifier to once again guarantee integrity.

Once the drying stage has finished, we recommend a laitance removal phase followed by a residual moisture content test to establish the suitability of your potential coverings.

Cement based aftercare

Cement based flow screed allows for much faster drying times than calcium sulphate screeds (Anhydrite).

A cement-based screed can be tiled at a final moisture content of 3.5%CM and timber floors can be installed at a final moisture content of 2.5%CM. This is a far quicker option compared to other liquid screeds which usually require some form of force drying via an under-floor heating system.

These screeds can be used in a non-heated floor environment as they do not require a force dry to remove excess moisture. Upon installation and by utilising the correct tile adhesives, tiles can be laid in as little as 5 days on a non-heated floor and in just 16 days on a heated one.

FlowTech UK

Work With Accredited Professionals

The FlowTech team comprises of Gas Safe Heating Engineers and accredited flow screed installers. We ensure that every installation we complete is done to the highest of standards guaranteeing you a high quality and energy efficient heating system that has been installed with your ongoing safety and comfort in mind.


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