Hi all you tilers.

One of my customers has used a flowing screed over a warm water underfloor heating. Unfortunately the underfloor heating prep was not great and a few of the pipes in one particular area have floated. It should have been sorted during the installation but for some reason was not. Anyway the pipes have floated to the extent that a couple of them have surfaced. i.e. No cover of screed on the pipe surface. some others have not quite surfaced so that they are only about 10mm or so below the surface of the screed. The screed needs 25mm minimum cover to the pipes to work properly so there is a risk it will crack when heated. I am trying now to help the client avoid digging out an area of screed along with the UFH by offering some options but am not coming up with very much.

There are a couple of questions. Has anyone ever used Ditra over this sort of mess - It would help to prevent problems of the screed becoming unstable.

Does anyone know if the use of Ditra would diffuse the heat from the UFH enough to stop the thermal expansion from destabilisig the tiles on the surface.

Has anyone got any other bright ideas that might help?

There is around 4 or five cubic meters affected and the tiled finish could be isolated with a joint from the rest of the tiles without too much esthetic disfunction. Obviously the client will have to decide whether to accept the risks of any solutions but he seems keen to do this rather than dig out the screed and re lay it.

Ditra will cope with the expansion no probs but i would still call technical in this instance to make sure of compatability..

Tel: 01530 813396

technical@schluter.co.uk