advice on floor, please

[burncross]

i'v been to measure a bathroom floor up today, (16sq/m) so quite big! they're already having some building work carried out on the house so the joiner's already ply'ed the floor. But with 6mm ply which is nailed down every 100mm?? the joiner insists that this is how he prepares all floors prior to tiling and other tilers have never said its unsuitable! but i've told them it needed to be 12mm and screwed down, but i think they're a bit reluctant to take it all back up now! Is ok to go over with 6mm hardibacker boards?

[TheWrightTiler]

shouldnt be nailed at all

screwd only

id insist he lifts and puts suitable ply down or walk away

[burncross]

i need the work so can't really afford to walk away. so if they insist on leaving the 6mm nailed ply, can i overlay it with hardibacker boards thats sat on adhesive and screwed ?

[Turkish]

Joiner isn`t tiling the floor, you are, and i personally would rather have piece of mind that the prep work was satisfactory. Backerboard doesn`t add strength but if you did that and maybe used fastflex or similar then you may get away with it! Do you just want to get away with it though?


Turkish

[grumpygrouter]

The thicknes of the ply isn't the real issue, the issue is, is the floor solid. Ply is only used to strengthen floors. If the joiner has layed the 6mm ply on to a solid floor i.e. deflection is withn BS tolerances then the 6mm ply lining is just to give a nice surface.

If on the other hand he has laid it to strengthen the floor then it is inadequate and should be corrected accordingly.

[Dave]

The thicknes of the ply isn't the real issue, the issue is, is the floor solid. Ply is only used to strengthen floors. If the joiner has layed the 6mm ply on to a solid floor i.e. deflection is withn BS tolerances then the 6mm ply lining is just to give a nice surface.

If on the other hand he has laid it to strengthen the floor then it is inadequate and should be corrected accordingly.

I would still recommend a 2 part adhesive on that floor...fastflex or similar.... as for bieng nailed..then just go over it with some screws....only if the floor is solid as grumps sez...

[andy-p]

wot dave said!! as long as the floor is sound , stick in some screws and fix with a 2part like mapei keraquik and latex fluid (much cheaper than fastflex) and you are sorted..

[grumpygrouter]

.......don't forget Ardex-flex 7001 as well guys.

[Dave]

.......don't forget Ardex-flex 7001 as well guys.

we won't grumps......i will have to try that one day..

[smokie899]

dave checked out your tiling store, your not much of a pro you. all that reading and no daily sport lol

[burncross]

so if its solid, i'l put some screws in the ply and use ardex 7001, i'v not used this before, is it a 2 part ?

[grumpygrouter]

Adrex 7001 is single part, thats the beauty of it! needs to be mixed thin so that you get a 100% coverage without back buttering. Great stuff in my opinion.

[burncross]

The thicknes of the ply isn't the real issue, the issue is, is the floor solid. Ply is only used to strengthen floors. If the joiner has layed the 6mm ply on to a solid floor i.e. deflection is withn BS tolerances then the 6mm ply lining is just to give a nice surface.

If on the other hand he has laid it to strengthen the floor then it is inadequate and should be corrected accordingly.

how can you check that deflection is within BS tolerance?

[grumpygrouter]

how can you check that deflection is within BS tolerance?

an excellent question indeed...........I wish I knew the answer. My normal way of checking is the glass of water test but this isn't foolproof!

[Dave]

how can you check that deflection is within BS tolerance?

Attach a string line and run it across the floor and attach at the other side something like 30mm above the floor......then when applying weight to the floor, either a second person or boxes of tiles ...check the measurement between the line and floor before and then after the weight has been added....if it exceeds more than 2mm or so then strengthen the floor.....just a guide to work from.....

[burncross]

cheers will try that one

[grumpygrouter]

Attach a string line and run it across the floor and attach at the other side something like 30mm above the floor......then when applying weight to the floor, either a second person or boxes of tiles ...check the measurement between the line and floor before and then after the weight has been added....if it exceeds more than 2mm or so then strengthen the floor.....just a guide to work from.....

Good tip dave.