Tiling on water resistant chipboard

[Martyn Leeds]

We going with the 9mm ply then?

 

[widler]

Id use HARDIE not PLY , much more stable ie it will not swell if it gets wet or when hot or cold 🙂
Marine ply will move as well.

Ps timber with move a tad even with the water in the addy when drying out

 

[SJPurdy]

Now 12mm is seen as the minimum if still using ply

I think that is 15mm ply now (but i'm not sure!).
As I understand it if new floor 300mm c/c joists noggins so that can fit new 15mm (min) ply. If exist floor with joists up to 400mm c/c then can overlay with min 15mm ply fixed at 300mm screw spacings or an equivalent tile backer board (6mm Hardie, 10mm Wedi etc). These for fixing ceramic tiles not stone. It would be useful to everyone, I think if this is corrected if wrong!

A note on the water getting into wood and causing it to swell: even if overlayed with a water proof tile backer board a leak under the bath can still get into the wood floor base and spread under the tile backer board causing it to swell and lift, thus cauasing tiles to crack (usually) at joits in the backer board. This has happened to me and required 150 mile round trip to replace the tiles.

 

[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

Hi there

How is the backer board fixed, you mention glue, would that be gripfill, or should I be reading this as floor tiling cement ?

Cheers

 

[John Benton]

Yep tile adhesive, floor cleaned and primed prior to this and spread addy with 6mm notched trowel and then screw down to secure. The screws hold the board in place, the adhesive fills any voids underneath.

PS Don't forget to make sure the screws are shorter than the combined thickness of the backerboard and chipboard, generally 20mm screws are fine

 

[Ivan Rubery]

Thanks, would fast setting floor flexi be the stuff to use ?

 

[p4ulo]

Yes, perfect.

 

[SJPurdy]

Ivan, yes it is cement based adhesive if it is Hardie backer board (and some other makes) as assumed in some of the above posts, but beware if it is "no more ply" board then use their special foaming adhesive as per their instructions.
I suggest you Google the brand of board you are being supplied with to get the data sheet for recommended fixing instrucxtions.

 

[Glynn]

Sorry for joining the thread so late on. Our S2 adhesive will fix tiles onto chip-board and we can say this with confidence, what we can’t say is that your chip-board is of a suitable type to be tiled on to. It has been well documented that tiling to chip-board can cause problems such as tiles de-bonding or the chip-board expanding and contracting due to the addition of moisture from the adhesives. Most chip-boards are not good for tiling because they are very unstable and not treated against the ingress of moisture and those that are rarely have the tongue and groove treated which is a passage for moisture ingress. If moisture gets in on these edges it can cause a problem called “grinning”, which causes the boards to curl up at the edges and could potentially cause tiles to de-bond. That said there are some better quality chip-boards around that can be tiled directly too. These types of chip-boards may have a vinyl/Formica type covering which will help in keeping the moisture out. There are some manufacturers that will say their chip-boards cannot be tiled onto directly because they are unstable, and with that information it would be hard to guarantee any product onto an unstable substrate. British Standards 5385 state that all substrates for tiling onto must be dry, strong, stable and clean. If the chip-board you would like to tile is not the correct type then I would recommend over laying it with a 6mm tile backer board. These boards will create a sound and stable substrate to tile onto. Also the Anti-fracture Matting is designed to absorb lateral movement in heated floors not to absorb deflection, it may add something to the make up of the floor but if there is deflection something more substantial will be needed, and do not forget no matter how flexible your adhesive is your tiles are not.

 

[SJPurdy]

Sorry for joining the thread so late on. Our S2 adhesive will fix tiles onto chip-board and we can say this with confidence, what we can’t say is that your chip-board is of a suitable type to be tiled on to. It has been well documented that tiling to chip-board can cause problems such as tiles de-bonding or the chip-board expanding and contracting due to the addition of moisture from the adhesives. Most chip-boards are not good for tiling because they are very unstable and not treated against the ingress of moisture and those that are rarely have the tongue and groove treated which is a passage for moisture ingress. If moisture gets in on these edges it can cause a problem called “grinning”, which causes the boards to curl up at the edges and could potentially cause tiles to de-bond. That said there are some better quality chip-boards around that can be tiled directly too. These types of chip-boards may have a vinyl/Formica type covering which will help in keeping the moisture out. There are some manufacturers that will say their chip-boards cannot be tiled onto directly because they are unstable, and with that information it would be hard to guarantee any product onto an unstable substrate. British Standards 5385 state that all substrates for tiling onto must be dry, strong, stable and clean. If the chip-board you would like to tile is not the correct type then I would recommend over laying it with a 6mm tile backer board. These boards will create a sound and stable substrate to tile onto. Also the Anti-fracture Matting is designed to absorb lateral movement in heated floors not to absorb deflection, it may add something to the make up of the floor but if there is deflection something more substantial will be needed, and do not forget no matter how flexible your adhesive is your tiles are not.

Excellent post.
So good I thought it was worth repeating.
10/10