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 ?

 

[Alan.P]

As long as there's no deflection in the floor it should be fine.

 

[Ivan Rubery]

Again, thanks for all the help

 

[AliGage]

No damage to the chipboard taking the Ply overlay up then?

 

[Ivan Rubery]

No, a few little holes where screws had been, but was thinking of just filling them, its not too bad

 

[AliGage]

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 !!!!

It's only you said the 9mm ply was cemented and screwed.
Have you managed to clean up the floor ok then?

The quickmat decouplers need a flat clean surface before fitting.
I still think you need to overboard the chipboard. Which raises you 6mm plus addy. I'm struggling to see how there is a concern over a big step up from the carpet. Underlay and carpet is what? 12mm.
So overboarding with a backer, addy, plus tile would create a step, worse case 8mm?

 

[Ivan Rubery]

Hi AliGage, yes it did not clean up too bad surprisingly. It looks ok to me to put this decoupling mat straight on to it. I understand what you are saying about the height. I have put a tile on top of existing chipboard near the carpet and it is slightly above carpet now, if I were to ply over with 9MM it would raise it considerably. Experience and knowledge in this game pays big dividends, without this it can be a bit sressful. I hope that I learn from this experience when I go to look at similar jobs !!! I am so glad that I got on here before I started, as I am sure many people have gone down the wrong path only to return at a later date to fix issues. Thanks again

 

[Old Mod]

As @AliGage says ur floor must be clean and flat! It's an ultra thin product and needs full contact.
If u have any adhesive residue there, either sand it off or skim with slc first.

 

[Ivan Rubery]

Thankyou

 

[SJPurdy]

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 ?

I would ask the manufacturer of the matting that question; will they guarantee its suitability?

 

[Old Mod]

I would ask the manufacturer of the matting that question; will they guarantee its suitability?

Here Steve have a look at this mate.
Anti-fracture Matting for Floors Subject to Limited Movement | Tilemaster Adhesives

 

[AliGage]

@Ivan Rubery. No one is suggesting 9mm ply. It's both inadequate and doesn't confirm to standards.

I personally don't think a mat us the way forward here. I would still go with a 6mm hardie backer or equivalent glued and screwed. I think I'm right in thinking this will bring you just below carpet height. So finished floor will be around 8-10mm.
Hardly a step, more than reasonable. You can't, infact very rarely cam you get a tiled floor to finish bang on level with an existing, adjacent floor covering.

 

[Spare Tool]

Another option if the only thing stopping you fitting a backer board is the height of the carpet, pull back the carpet, prime and skim a small ramp out of tile adhesive thus lifting your carpet height, finish with a flat thresher strip..

 

[MW Smith Ceramics]

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

 

[MW Smith Ceramics]

Hi mate,

I always use Schluter ditra matting on good chipboard floors with very little or ideally no deflection stuck down with ardex AF200 but if there is too much movement there then I would definitely go with a 6 or 9mm backer board glued, screwed & taped and if there is a bit of a step coming into the room I always use some thin layers of underlay to create a bit of a ramp if need be.


Hope that helps

 

[Ivan Rubery]

Hi mate,

I always use Schluter ditra matting on good chipboard floors with very little or ideally no deflection stuck down with ardex AF200 but if there is too much movement there then I would definitely go with a 6 or 9mm backer board glued, screwed & taped and if there is a bit of a step coming into the room I always use some thin layers of underlay to create a bit of a ramp if need be.


Hope that helps

That's great advice.

I have had lots of different ideas on here and this has helped me a lot in deciding what I should now do. Thanks to all who have contributed to this thread.

 

[SJPurdy]

Here Steve have a look at this mate.
Anti-fracture Matting for Floors Subject to Limited Movement | Tilemaster Adhesives

Thanks for the link. It is the same with countless other manufacturers with their anti fracture/decoupling membranes, they are designed to do a job and allow for (the unspecified) "limited movement" in the substrate. I admit I am a bit sceptical (hence my earlier post) as they have been around in various forms for years and I have seem them not cope when presumably the movement exceeded the "limited movement".
I also note that many manufacturer's have designed tile adhesives to fix directly to the boards. The rubber crumb type for example cure to a bed under the tiles that will also allow for limited movement; but I along with earlier posters in this thread would not recommend this method (even though I have fixed many floors this way with no problem).

The key with the floor under discussion is to make sure it is firmly screw fixed down to the joists so that the floor is rigid with no discernible movement and that any joints are supported. The original poster can then choose from the methods given above as to how to prepare for retiling. If height is a major issue then the decoupling/anti-fracture membrane way will be the thinnest. Personally I would prefer to overboard with 6mm Hardie backer board (fixed to manufacturer's spec) because I perceive that this gives some increase in rigidity to the floor. I would also consider 6mm "no more ply" (fixed to manufacturer's spec) but only if the surface of the chipboard is very flat.