floating floor - Tile Advice

[Matty A]

i have a customer wanting 1.6m2 of slate laying when i went to look at the job i lifted the old lino in the room and discovered that the sub wasmouldy and appeared to be rotten now the sub is 18mm chipb'd (floating) on top of 2" polestyrene ontop off dpm and concrete.
I wanted to cut out the damaged chipb'd, fasten some 4"by 2" to the dpm and conctrete then fasten 18mm ply to that and tile striaght on top thus redusing the step into the room.

But the building contractor has said there is nowt wrong with the chipb'd and to use some type of fungicide remover to get rid of the mould.

My question is shall i overlay with ply and will screwing it into the chipb'd be ok or i thought i could overlay with ditra i am gonna phone schluter as well just wanted to know if anyone can offer any advice.

Also i dont think the existing chipb'd is of p5 grade (water resistant)(green stuff)

Cheers.

 

[Dan]

I'd replace it with the green stuff or marine ply (or similar) and then tile over that as usual.

I'd also consider using Fastflex or something similar too as it doesn't sound too solid to me.

Schluter isn't the way to go here I don't think, it isn't really designed for that sort of thing.

Hope this helps Matty.

 

[UKTT Darren]

floating floors are not the best of floors to be dealing with, I would be putting 18mm exterior ply down, this is the british standard for plying out , its the only thickness that will produce no movement, treat the existing floor, use a liquid nails and screw down every 300mm, watch out for pipes

 

[MIKETILER]

I went to see a kitchen floor last night,where the customer had a new kitchen fitted about 10 months ago.They also did the tiling.Within 4 weeks of the tiles being laid,the grout started to lift.They have regrouted in the areas that have been lifting but to no avail.Looking at the grout it seems that even where it hasnt lifted,it hasnt adhered to the tile,leaving small gaps.It looks as though they have plyed onto concrete before tiling but I would not be too sure until I have lifted them.It is a 60s house,so I would be surprised if it is floorboards on the ground floor.Also when you walk on certain tiles you can hear a small crack,I dont feel any movement but I cannot think of what else could be causing this.I could try a flexible grout in there,but I dont think that the overlying problem would be solved.It certainly would be a huge job having to rip up the tiles and ply and start from scratch and would cost the customer or the kitchen company loads of bucks.
Anybody else had this problem
Mike

 

[L & R CERAMICS]

try mixing more of flexible additive into your flexible grout and make it sloppy rake all your joints out and push it all in ,sounds like these tiles may have been laid in a hurry and dot and dabbed so there may be empty pockets under and around the edges of the tiles ,done a re grout a couple of months ago on a new conservatory floor which sounds like you got the same problem ,let us know how you get on

 

[MIKETILER]

Thanks L &R
Will let you know how I got on
Mike