Help!: the Tiling Sherlock Holmes required

[Jones]

Hello tilers! I have been tiling for around a year now and most of my jobs have been quite conventional and straight forward.

I have been asked to sort a problem in a customer's bathroom where the tiles are popping up from the floor. It seems as though the wooden floor was covered with OSB (Hmmm..) with an underfloor heating system ontop, and then tiled over with a ceramic floor tile. I think a lot of the problem is due to the wrong adhesive being used but I also fear the OSB may need to be replaced. We pulled-up a tile and the white adhesive was crumbling - It didn't appear to be a flexible adhesive.

He has a seperate shower cubicle and in there the tiles have popped-up also. The customer is sure there is a waterproof membrane underneath these tiles but the same problem has occured. Does this point to the fact that the wrong adhesive was used throughout? If it was the OSB causing the problem, it shouldn't have caused a problem in the shower cubicle as (apparently) that is water tight.

I want to help the guy but I'm not Lieutenant Columbo and I don't want the problem to return. Should I replace the OSB with marine ply and start again?

Any help is greatly appreciated

Dom

[david campbell]

i would rip up the entire job and start again,as you say the osb is not suitable for tiling onto(it tends to be made from wood chippings) i would replave with at least a 12mm ply or 6mm cement boards depending on the movement the floor has,the only problem is however lifting the ufh without damaging it,i think that is going to be the hardest point

[incetilingltd]

Lift up is my opinion aswell i'm affiad also if you do re-tile let the customer know a suitable wait time for the ufh common problem i'm having is the electrictian is wiring it up and turning it on within a couple of days after i have finished, and a simular thing is happening.

Good luck mate

[jay]

okay hi can you explain just for me please 1 you have a timber floor 2 osb chipboard i think 3 waterproofing 4 under floor heating 5 any leveling comp 6 tiles and adh not sure on osd and is this the floor make up thanks

[dock]

OSB or Stirling Board as it is also know is a board made under high temperature and pressure and the manufacturers of this board will confirmn that it is not suitable to be tiled.

In order to provide a tiled finish i would suggest you proceed as follows;

1 Take up the existing tiles and Oriented Strand Board.
2 Secure either minimum15mm exterior grade or WBP plywood or a suitable cement
board at maximum 300mm centres.
3 Refix the under tile heating
4 Prime with Mapei Eco Prim T
5 Encapsulate with Mapei Fiberplan
6 Comission Under Tile Heating
7 Fix in Mapei Keraquick
8 Grout minimum 3mm joints with Ultracolor Plus (26 colours)
9 Movement joints may be filled with Mapesil AC colour to match the grout

Hope this helps as I am sure there are other views

dock

[Jones]

Thank you for all your help, Gents. I thought that would be the answer but it's nice to have your experience on my side. Good stuff. Cheers