Floor preparation · · Shane, Deluxe Tiling
Tiling over underfloor heating: how to avoid cracked tiles
Underfloor heating and tiles are a great pairing — if the floor is prepared for the movement heat brings.
Porcelain and stone are ideal over underfloor heating: they hold heat well and feel warm underfoot. The risk is movement — heating makes the floor expand and contract, and that can crack tiles or grout if the floor isn't prepared for it.
Let the screed dry and commission the heating
New screeds need time to dry, and the heating should be commissioned — brought up to temperature slowly and cooled again — before tiling. Tiling too early is one of the most common causes of cracks.
Where an uncoupling membrane helps
An uncoupling membrane such as Ditramat sits between the screed and the tiles and absorbs some of that movement. It is often worth adding over heated screeds, timber floors and new extensions. Whether your floor needs it is checked at the survey.
Turning the heating back on
Once tiled, the heating is brought back up gradually after the adhesive and grout have cured. Always follow the manufacturer's guidance for your heating system and adhesive.