Tiling on water resistant chipboard

[Ivan Rubery]

Hi there

I am new to this and I would just appreciate a little bit of advice. I have searched various forums and cement manufacturing companies who claim that chipboard flooring can be tiled on as long as the floor does not move, there are no gaps and that boards are screwed at 300MM intervals. I have looked at Tilemaster ultimate S2 flexible and it does appear to be for this kind of flooring.
The floor does feel quite solid and on top of the chipboard was 8MM plywood which had a vinyl on top. I had to remove the plywood as floor was too high, or would have been. This was cemented and screwed to the chipboard and was a lot of fun to remove !!!!!
I am in a dilemma as I told customer it could be done, however the thickness of the tiles are 9MM and I don't want to raise the floor any more as there will then be a step up to the bathroom.
My only other possible fix is to remove the 18MM chipboard flooring and replace with 18MM exterior grade plywood which would be quite a bit of work for me.
The floor is in an upstairs bathroom and rests on 400MM joists.
Please any help would be great

 

[Alan.P]

I wouldn't fix straight to chipboard, regardless of manufactures claims, I would fit a de-coupling membrane like Ditra or other, then fix to that.

 

[kevsalt]

as above or no more ply all over screwed at 150mm centres

 

[Dave]

Tiling direct to a particle board is a BIG no no , no matter what adhesive comps tell you.. Adhesives will stick to it yes , but the integrity and longevity of the installation will be minimal IMHO .

 

[AliGage]

If deflection free it'd be 6mm hardie glued and screwed.
What do they gave on the floor outside the bathroom that means you're worrying about height? Lino??

 

[Chalker]

9mm no more ply, or the same in insulation board is a minimum on a chipboard type floor.
You will still only have 20mm of build up, which if the customer is having carpet, the level difference will be a few mm .

 

[Ivan Rubery]

Thanks guys. Oh dear looks like I will be replacing the 18mm chipboard with plywood. At the end of the day I dont want to be going back there !!!! I was just hoping that there would be a slight possibility of not having to do this. If I did put the 9 mm over existing floor and then the 9mm tiles it would be quite a bit higher than carpet outside.

 

[AliGage]

There have been three other suggestions of how to prep the floor. No one said you have to remove the chipboard.

Even if you replace with ply it would be suggested to overboard with a backer or decouple.

 

[Old Mod]

Thanks guys. Oh dear looks like I will be replacing the 18mm chipboard with plywood. At the end of the day I dont want to be going back there !!!! I was just hoping that there would be a slight possibility of not having to do this. If I did put the 9 mm over existing floor and then the 9mm tiles it would be quite a bit higher than carpet outside.

Maybe u should consider a decoupler from Tilemaster or Bal @ > 1mm thick.

 

[Ivan Rubery]

Maybe u should consider a decoupler from Tilemaster or Bal @ > 1mm thick.

 

[Ivan Rubery]

Ok thanks, brilliant advise, i really appreciate the help on here. The customer looked annoyed when i told her about the floor and kept asking how much. They are already recycling the radiator and taps that i have removed for cash, and keep saying thry dont want to overspend !!! Sometimes i wonder about folk.

 

[Old Mod]

Well tell them they'll be spending double if they don't spend an extra £100 now!

Anti-fracture Matting for Floors Subject to Limited Movement | Tilemaster Adhesives

 

[Ivan Rubery]

Thanks for the link

 

[Dan]

Sounds like we need a test, deaaaannooooooooo?!?!?!

 

[Ivan Rubery]

Brolliant advice, thanks very much.
1 more question, will the existing 18mm chipboard be strong enough if I use this anti fracture matting. The floor tiles are ceramic, 9mm thick and about 300mm square ?