Floor preperation help

[george792]

Hi all,
have just been to look at a bathroom job and the lady would like the floor tiling with granite tiles. The floor is chipboard floor, I know the floor needs strenghening and was thinking marine ply and use flexable adhesive.This will raise the floor and create a step up, I was wondering if there are better ways of doing this to get a better finish and do a good job all advice on this and adhesive+grout appreciated newbie tiler.

[grumpygrouter]

The issue George is how solid the floor is. If it is solid, you can use 6mm hardiebacker. If there is deflection you will need to strengthen the floor. WBP or exterior grade ply would be sufficient, marine ply is very expensive.

How big is the floor?

[george792]

Hi grumpy the floor is only small 2 m2 but the floor does have movement I am going to remove sink and toilet so the tiling is fairly straight foreward was thinking of WBP 12mm but again thinking of the step up are there any products for a good finish

[grumpygrouter]

Is the movement because the chipboard is loose on the joists or is it deflection of the joists themselves? 2m2 is not a big area and I would have thought any movment would have been minimal.

As it needs strengthening the best way is to ply out and really it should be 18mm but you MAY get away with 12mm. My house has timber door transitions made for hardwood about 20mm thick and 30mm wide running across the doorway. This might be the neatest way of finishing off and use silicone between it and the tiles.

[george792]

Cheers grumpy thinking floor movement is loose board have advised customer about possibilty of movement and work invloved any advice on adhesive and and grout cheers again

[grumpygrouter]

My own persoanl favorite for timber floors is Ardex-flex 7001 and Mapei Ultracolor Plus grout.

If you go the BAL route, they would expect at least 18mm ply if you want to use SPF or rapidset flex. Anything less and they specify Fastflex. Warranties are a problem with them otherwise.

if the floor is only 2m2 and the suite will be out and possible no skirting boards, then have you thought about removing the chip board and re-laying using 18-25mm ply screwed every 225mm. this way you reduce the height and give the floor the rigidity it requires??

its quite straightforward to do if everything is removed. nailed chipboard just be banned!!

[george792]

Thanks tile burden only had thought about taking out existing floor but she is keeping skirting and not removing bath so was thinking more trouble than worth