Hi there....looking for some advice. To cut a long story short I have lifted the old bathroom floor and have exposed all of the wooden joists. Unfortunately most of the joists are a different heights so getting a level floor is going to be pretty tough. They vary by 5-6mm in places and not one of them is level!! The tiles are going to be 450mm x 450mm. Going to take ages with packers to get floor level so I thought about screwing down 18mm ply onto joists, use a self leveling compound and then put down 6mm tile backer. Will this work? What would you do? Floor size is 3.8m by 1.6m.

Note: I use mapei fibre plan on my underfloor heating but it is way to dear for this job. any other makes for this job?

Thanks for reading. SA

i would lift floarboards and put down 22mm ply, then slc(try sika from b@spew) wouldn't bother laying the cement boards on top of that though!

Thanks, all floorboards are up. 22mm ply is difficult to get here and 25mm is a bugger to work with. Do you know of any suppliers in Glasgow south. B+Q no and Jewson no......

.......and was thinking that the cement boards would overlay ply joins......

b&q in east kilbride occasionally stock it,either that try the timber merchants like east end saw mills

you will find the timber merchants are also cheaper than the diy stores by a good bit if you open a trade account with them

i would pacck it have a look at these
ASSORTED PLASTIC PACKERS LEVELLING SHIMS BATTEN 45x55mm - eBay Other Building Materials, Building Materials, Hardware, Construction, Business, Industrial. (end time 09-Nov-09 15:03:35 AEDST)

After laying 6' level across joists.........can you not cut shims for the lowest joist to level/flatten it out?

Then 22mm ply it?

cant help but think that using slc would save time as the joists are all over the place.......

Mapei fibre plan will do the job, once you replace with ply...

have you questioned why the joists are uneven?
bad job done previously?
or rotting joists at the ends, that have caused the drop. if so, may have to think about maybe replacing some joists....
just a thought...

Originally Posted by Superally

cant help but think that using slc would save time as the joists are all over the place.......

yes i would but imo not as good a job

Could overlay joists with ply as they are and then take out the level issues using Laybond Woodsmooth or something of that nature.

Hello everyone. Thanks for all your replys. Decided to use shims after I checked for rot at both ends (which there was not). Some great ideas shared. SA Great Forum!!