Chipboard floor in a new build.

[Greyhead]

Hi all have been reading forum for a while but not posted before, I have been asked to quote to tile floors in a new build flat, (6months old) 20m2 in total, all floors are green chipboard, he wants slate ideally but wants a quote for both ceramic and slate, the job consists of:
Entrance hall -Tshaped 1.3m at widest point
Under stairs cupboard
Small bathroom downstairs
Upstairs bathroom
All floors are solid and fairly level. Any wooden floors that I have done before I have always used 18mm ply that I put down myself and put over the recommended amount of fixings in, then used either Fastflex or Ultimateflex so I was as sure as I could be that there were no problems. Having read the forums I still am not sure if I can lay tile on green chipboard or not, if it was primed would either of the above be ok to use or do I have to put some backerboards down first or could I lay 6mm ply instead to keep the cost down for him? Any help with adhesive or preparation would be great as chipboard is a bit of a mystery to me.
Thanks in advance
Greyhead

[grumpygrouter]

Hi Greyhead, would you be good enough to introduce yourself in the "New Members" section and tell us a bit about yourself? Cheers.

Fastflex is suitable for tiling straight onto chipboard if you really want to. The idea of overboarding is to add strength to the wooden floor. British Standards recommends a minimum of 15mm for overboarding.

If the floor is absolutely solid, then it is not necessary to overboard, IMO. There will be all sorts of responses to my statement but as yet I have seen nothing that has made me change my mind. Many guys now use backerboard instead of ply, Hardie do a 6mm version and so do No More Ply I believe.

Backerboard is usually laid with a thin bed of adhesive and then screwed down. Personally I don't believe that 6mm hardie adds much strength to the floor, neither would I use 6mm ply. I overboarded my own kitchen floor with 9mm ply but my floor was solid prior to that and I did it as an experiment as I was newly trained. Floor is still in 1 piece with no cracked tiles or grout, coming up to a year on. I used Ardex-flex 7001 after priming with Ardex P51. Also used Ardex-flex FL grout.

Grumpy

[Dave]

Also if these chipboard floors are down stairs as you say..then they could be floating floors ( tongue & grooved laid on polystyrene)...And i wouldn't touch a floating floor with a barge pole but some fixers will...for me to high a risk of tiles de-laminating......what ever the prep work...........

[pjc]

green chipboard is not the best thing to stick to not as good as normal chipboard but can be done with a 2 part adhesive but as grumpy said but most say don't prime check first as Dave says floating floors are a no no no i would screw it to the joists then fix 10mm tilebacker board to it with 2 part then tile it :Pete

[muffinman]

did a floating floor used ditra matting no probs

[Mike Strutter]

I've got a conservatory to do next week, and it has had these green tongue and groove chipboard sheets laid. There is a UFH system installed but it's the pipe system so it's laid between the joists, the builder has told me that the boards are screwed down onto the joists. I'm laying Travertine, so should Ardex-flex 7001W be my choice of addy if i fix staight onto the boards? And should i prime/seal the boards first?

[grumpygrouter]

Originally Posted by Mike Strutter

I've got a conservatory to do next week, and it has had these green tongue and groove chipboard sheets laid. There is a UFH system installed but it's the pipe system so it's laid between the joists, the builder has told me that the boards are screwed down onto the joists. I'm laying Travertine, so should Ardex-flex 7001W be my choice of addy if i fix staight onto the boards? And should i prime/seal the boards first?

Ardex will do the job fine - as long as the floor is solid!!! Prime with P51 primer, neat and leave to dry. if it was me and assuming again the floor is solid, and because you are laying travertine I would consider laying Ditra first as you have UFH.

[Mike Strutter]

Cheers Grumpy, i,ve also got two bathrooms upstairs to do and it's the same stuff on the floor, again with travertine.