Installation & Drying

  • The site must be accessible with a concrete mixer lorry.
  • An outside water supply must be available on the day of installation, gradually bring the temperature of the underfloor heating up to ambient temperature and hold this for 2-3 days.
  • A skip or other means of disposing excess material and washing down the pump must be available on site.
  • If we are supplying material on to your preparation, the preparation MUST be up to standard, all joints must be taped securely, perimeter edge fixings must be in place and secure, insulation must be flat and not rocking or moving under foot and very importantly all under floor heating pipes must be firmly fixed and unable to lift during the installation.
  • The preparation must be clean, free from dirt and debris.
  • The site must be in the dry, any windows or doors should be closed during installation and the rooms must be free from strong draughts.
  • Please remember that our screed finish is only as good as the preparation.
  • For specific site requirements please refer to our quotation.

After care and curing times

  • For the first 24-48 hours the floor MUST be kept dry and draught free.
  • Do not walk on the screed for approximately 36 hours after it has been laid. After this period windows may be opened to allow the room to ventilate and dry.
  • The material will have a natural film on the surface at this time, this is normal and is called laitance, the majority of this will remove through general foot traffic. The remaining may need sanding to remove.

A typical drying time for calcium sulphate based screeds are:

1mm per day up to 40 days then 0.5mm per day beyond to the installed thickness. For example a screed laid at 55mm thick will require 70 days to cure and dry.

Obviously if the floor is not kept dry over this period it will prolong the drying time.

Please remember we can install fast drying screeds that will be dry and cured ready to accept floor finishing’s within 14-21 days.

Unlike the standard mortar screed, the calcium sulphate based liquid screed can be force dried using the under floor heating system following these guidelines.

  • Naturally air dry for the first 14.
  • Commission the under floor heating and bring the temperature of the room up to between 18 – 24 degrees, hold this for 7 days.
  • After the 7 days, gradually increase the temperature by 1 degree per day up to maximum running temperature (not exceeding 50 degrees c). Hold this for up to 2 days.
  • Gradually bring down the temperature by 1- 2 degrees per day back to ambient temperature.
  • Leave to cool and the floor will now be ready to prepare for tiling.


  • Moisture content should be 75% humidity prior to tiling, ie 75% dry.
  • All remaining laitance must be removed.
  • The under floor heating must have been commissioned.
  • The screed is a calcium based product and is NOT compatible for standard cement based adhesive to be used, you must use a calcium sulphate based tile adhesive.
  • This is easily available from any good merchants and should cost no more than normal cement based adhesives.
  • The floor should be prepared with a specific sealer designed for the screed prior to tiling.
  • We can supply you with the adhesive if required, please refer to our shop page (supplies) for details and costings.


For further information regarding installation, depths, quantities and after care please do not hesitate to contact us.

We have great technical back up from all major suppliers.