Liquid Screed – (Preparation for Floor Finishes)

Floor Finishes

Underfloor Heating Commissioning
This must be commissioned and run prior to floor coverings regardless of how dry the screed may be. This is to keep in line with CFA, TTA, Vinyl and Tile Manufacturers guidelines. This process forces additional moisture from the screed and conditions it to thermal movement prior to coverings, typically the commissioning cycle is 21 days and can start 7 days after the screed has been laid.

Moisture Testing
The natural drying time is 1mm per day up to 40mm and 0.5mm after that. However, the drying times can be greatly affected by site conditions, so it is advised that the atmosphere be kept as warm and dry as possible to improve this. Prior to coverings the screed moisture must be tested using either a hair hygrometer carbide bomb or oven test and below 75% RH (0.5% Moisture).

Sanding
Sanding is required when tiling is the finished floor, or any other floor coverings that will be glued to the screed. This will remove any laitance, ready for priming. This process is very important and must be done correctly to avoid any problems with tiles lifting in the future!

Please call us if you would like to make arrangements for us to do this.

Priming
Priming is required prior to application of adhesives for two reasons:

1. To seal the porous surface to prevent suction of moisture from the adhesive or smoothing compound.
2. To form a barrier between the screed and any cement based smoothing compound or adhesive.

Primers are generally Acrylic dispersion or Water based epoxy and generally perform better used as a two coat system. However, the manufacturers must be consulted for recommendation on its use. Please call us if you would like to make arrangements for us to do this. We sand and seal during the same visit providing the floor is sufficiently dry.

Further Information

More Uzin Technical Data Sheets