floor tiles just been put down on top plyboard which is on top of floorboards, a couple of the tiles are rocking slightly and grouting has cracked around them

hi yes call back the tiler ,,,sounds like he has not bedded the tiles properly ..i.e put down an even layer of tile adhesive ...so when you walk on tiles they start to rock and the grout cracks...defo down to the tiler ...make sure they remove loose tiles and rebed ..dont let them just regrout this will crack again .. all the best

hi all floorboards need to be secured to joist first with floorboarding nails then 12mm plywood needs to be screwed to floorboards sounds like either floorboards or ply are not fixed securly as your grout cracking is a classic sign of your problems regards bob

The tiles are moving because the tiler has not put enough fixing screws in the ply subfloor.There should be a fixing every 6" in every direction.Only way to rectify this problem is take tiles up and fix ply properly.If the tiler fixed the ply down then it is most definately his responsibillity and he should come back and rectify the problem. Hope this helps.

Hi, Movement that has caused this. Was a flexible adhesive and grout used? I can repair the tiles but I would say that they would have to come up and be re-layed. Hope this helps Jason

This is caused by movement in the floor which has to be compensated by using flexible adhesive & grout. Also sound like he's hit a hump in the floor which has caught the middle of the tile & he's not put enough adhesive either side, causing it to rock. Definitely call the tiler back. Hope this helps, good luck. Michael

How long have tiles been down ? maybe the ply was not sealed before hand hence why tiles have not stuck or ply is too thin the ply should be sealed with a PVA based product or watered down PVA so wood dose not draw moisture out of adhesive, either contact a tiler or try lifting loose tiles chipping of existing Adhesive from ply then sealing and relaying tiles allow to set overnight without walking on then grout.

well, yes you should call them back. They should have used flexible adhesive and grout when tiling onto wooden floors, so if they have done this, this should't be happening, so i'm guessing they haven't. it might be a case of taking them up and doing it again.