Hi

I'm a real newbie to tiling and have a quick question for the experts... Is it possible to use a thicker layer of tile adhesive during tiling to make a slope to match variations in sub-floor levels (floorboards)? I'd rather not overboard with really thick ply in this situation as I'm limited in ceiling height etc, what makes things complicated is that the floor already has a slope, so I'm not sure overboarding would help in that case, as it would just raise it.

So I'm wondering wether it would be better to use more adhesive to level it up as I go.

If so what is the max thickness of adhesive I'd get away with - and are there any issues with putting down loads of the stuff?

hi Derek

to the best tiling forum in the world.

what room are you planning on tiling? and do you know exactly where it slopes and by how much?

give us as much information as you can and the guys on here will do their best to help you

Hi GirlRacerRed - its in a bathroom, and it slopes about 10mm quite noticably over a metre approx in 2 axes rather than just one direction which complicates things obviously!

is the bathroom ground floor or first floor Derek?

you could take up the old floor boards and replace with wbp ply the same thickness. to keep the levels you want, uou could also strengthen the floor with extra noggins between the joists.

Thanks for the suggestions, Ply isn't a solution for this because it just raises the level of the slope of an already sloping floor by 18mm - which doesn't actually help in this case.

The slope seems to be due to the joists loading over the years meaning the old building not being perfectly level now. Construction wise its a suspended floor over a US style 18" crawlspace void - although sleeping walls make it difficult to access.

The slope isn't in one direction, its in two directions, which means packing joists from the underneath isn't going to help much.

Regrettably Its also too difficult to remove the floorboards to get to the joists as there are partition walls on top unfortunately which is why I want to try to correct the slope on top instead somehow - hence why I was thinking of putting loads of adhesive down, using that to level it off or alternatively some kind of screed instead over the top of the floorboards to make it level.

So can I use lots of adhesive to do this? Or should I be screeding?

as above and you can use thickbed adhesive, but to be honest its not easy to trowel different thickness and keep the floor free from lippage, addy at differant depths can pull back when drying causing an uneven tiles

if your worried about height issues then as Nybor has mentionrd itd better to take the floor up and relevel by fixing 2x4 alongside the existing joists to level the floor, its worrying when I hear of a wood suspend floor diving that much as it could be joist problems, adding the weight of tiles could make the problem worse

my advice to you would be to take some boards up and investigate before going any further

if theres any deflection at all in your floor it will need taking up and bracing, fixing 18mm wbp , and overboarding with a tile backerboard, if you need further advice on what this involves we will be more than happy to talk you through it

there is something called a Self Levelling Compound and it pretty much does what it says, self levels!. create the boundaries that is as far as you want it to level, mix, pour and then it finds its own level, filling in the dips as it spreads out. but I'm not sure that SLC would be appropriate here. maybe one of the pro's could input their views?

from what you're describing, the bathroom is a suspended floor. do you know how thick the floor boards are?

is it just the floor in the bathroom that slopes?

derek

our posts crossed, theres not usually excessive deflection in floors supported by sleeperwalls

Hmm - self levelling compound might be the best option in my case that would solve the diagonal slope - thanks for all the helpful suggestions

are these tongue & groove floor boards

Originally Posted by nybor62

are these tongue & groove floor boards

my first thoughts too mate