hi guys hope all is good.
Im tiling three floors in a new build. A downstairs toilet 1sqm concrete floor.An en suite 2sqm chipboard floor and a 3sqm chipboard bathroom.The problem im having is that the two chipboard floors dont seem to be screwed down.The floors are made up of about three panels but am not sure how they are stuck down.There is no movement whatsoever and are very solid.Down the hole where the sink pipes go the board measures a 30.5mm thickness also it looks to be as its two layers so am not sure wether the bottom layer is screwed and the top glued onto that.Again the floor is very very solid and has no movement.How would i tackle this? With the floor being as solid as it is would it be ok to put "ditra matting" down and tile onto that as the floor is solid and wouldnt be using it to replace ply but just to give a surface without the step to tile onto.Sorry its long winded but needed advice.The tiles im putting down are 400x400mm porcelain mosaics.Thanks and hope you understand what i mean

Is it a "floating floor"? if so you could end up with problems.

I have a wee bit of experience with new-build and would have to say this sounds a bit odd !! ....are the en-suite and bathroom upstairs davey ??? ....if so, it's hugely unlikely that it's a floating floor. It's unusual to be 30mm thick upstairs (normally 18mm) .....the only time I've known it to be 30mm is where the builders, architect or staircase supplier has cocked up and they have to pack the floor height up to make the staircase fit ....hence - overlaying a 22mm chipboard on to the existing 18mm to gain the height .....that sounds quite possible in this case, it's also highly likely that the joiners have just not bothered screwing down the top layer as they already know the 18mm base layer is screwed down .....FYI - joiners quite often "conveniently forget" to screw the floors down in new builds ! lol

If I were you mate, I would try and ask the builder why it's 30mm ....failing that - maybe speak nice to a neighbor and see if their floor is the same ?

Might be worth reading this thread - Quick question - tiling to wood

Interesting question about the Ditra matting to avoid the height issue ....sounds like a good plan to me, but I'm not experienced enough to advise on that ...be interesting to hear what the others think though

i dont mean to sound stupid but what is the difference between the two? i have an idea but is something i'd like to clear up and know for future thanks grumpy.

hi allure thanks for the reply pal, i think that what your saying maybe right about adding extra layers to gain height and that they didnt screw it down.Only problem i have is that cant get hold of the joiners and the guy im tiling for doesnt want the floor pulling up to look whats going on under there.The two floors are upstairs and do seem very solid enough to tile onto,obviously with a layer of "ditra" or "hardiebacker" on.What do you's suggest? Also dont think the neighbours want me pullin their carpets up bit snotty if you catch my drift lol

Originally Posted by davey-j

i dont mean to sound stupid but what is the difference between the two? i have an idea but is something i'd like to clear up and know for future thanks grumpy.

A floating floor is a floor that has a thin insulating layer underneath the main floor surface. This surface is not secured physically to anything else as such so it "floats" on top. Because the insulation layer can compress, this can cause movement which may lead to the tiled surface failing.

a suspended floor is a floor made up of timber joists with some sort of board (like chipboard) screwed to it. It is a more secure surface to tile onto.

No bother davey ...as before, I think it's unlikely it's floating ....but, yeah - you don't want to be pulling things up to check ! lol ....maybe ask your customer to speak to a neighbor ....just so you can see the floor thickness at the bathroom waste pipe hole ...if it's 18mm then most likely it's just been a cock up with your customers floor height ...if it's 30 then you need to suss out why mate.

As before ...I really don't know enough about the ditra matting but I'd say that's belt and braces and seems like a good plan ......could somebody else in the know please confirm this ?

ill try and get him to have a word with the neighbour then pal cheers for the advice.
hi Grumps got the general jist of the difference between the two now ta. Looking at it,it is definately not a floating floor and just seems to be more what allure was getting at if thats any help.What do you reckon pal? should i screw the floor down securely then put some "ditra down" or would you do something totally different? just trying to get a few angles on what to do as the floors seem pretty solid to me and have no movement whatsoever
Thanks again all

Me personally, I would screw down the board at 300mm intervals to eliminate any movement, then overlay with Ditra-Matting and flexible tile adhesive.
You can't go wrong if you are adding extra screws to make the floor more stable. Movement is an enemy of tiles.

Yes mate ...if you know it's not floating then just as 55 says, cheers