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https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl DIY Forum >> Painting, Decorating & Tiling Questions >> Tiles moving and grout falling out https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl?num=1487332379 Message started by digitben on Feb 17^th, 2017, 11:52am

Title: Tiles moving and grout falling out
Post by digitben on Feb 17^th, 2017, 11:52am

Last May we finished renovating our house including insulating the floors and installing Solflex underfloor heating. We then had tiles laid although already the grout is cracking between the tiles/ falling out in places and some tiles moving when you stand on them. One has even cracked since its not really supported underneath.

I’m not sure whether its the fault of:

1. the underfloor heating since it seems to come on fairly strong then cool off again quickly. As opposed to what I assumed would be a more gentle heat.

2. the concrete wasn’t cured properly before the tiles laid.

3. the tiler didn’t prime the screed (well enough) or use enough adhesive for the tiles.

Otherwise does anybody have any ideas?
Much appreciated
Ben

Title: Re: Tiles moving and grout falling out
Post by woodsmith on Feb 17^th, 2017, 1:45pm

Underfloor heating shouldn't repeatedly cycle from hot to cold and I think it would be a good idea to get the controller checked, then get the tiler back and see what he has to say.

Title: Re: Tiles moving and grout falling out
Post by CWatters on Feb 22^nd, 2017, 4:08pm

What type of screed/concrete was used?

http://www.bal-adhesives.com/tiling-onto-calcium-sulfate-anhydrite-screeds/

"Tiling onto Calcium Sulfate (anhydrite) screeds"

"Laitance is a weak layer of fine particles deposited on the surface of the screed as the anhydrite cures. This layer is too weak to tile onto and can also inhibit drying of the screed. Many of the failures we see are as a result of contamination of the adhesive by laitance"