We're converting the corner of a bedroom to a 1.2 x 3m en-suite bathroom (shower, actually).
When we removed the carpet we found there's existing 11m ply lying on top of 28mm floorboards (original old timber ones, not T&G) which sit on 8" joists. The span of the joists is 5.5m.
My tiler/plumber has started using this existing 11m ply (which is porbably not WBP ply) for the overboarding. So floorboards + ply is total about 40mm. He says he's going to screw it down very well so it won't move. Indeed I can't feel any movement.
I'm happy to go with this if: (1) he screws both floorboards and ply really well, (2) flexi adhesive of course and (3) *maybe* add ditra matting in case of small movements over time.
edit: Worth noting the shower tray is 1.2x0.8 so might be used by a couple at the same time
1. Will this be ok long-term? (The job is already well underway, so if I force him to change to e.g. 18mm WBP ply I'd have to explain why I'm insisting.).
2. Is the ditra matting a must in this instance? The reused 11m ply is presumably not WBP, but will a ditra mat also provide moisture protection to the ply? (There's no pipework in the floor except the waste from a sink and shower).
3. If the 11m ply + ditra is too risky, what's the lowest-hassle way of improving this? (6mm backerboard on top of the 11m ply?)
amny thanks,
Ash
When we removed the carpet we found there's existing 11m ply lying on top of 28mm floorboards (original old timber ones, not T&G) which sit on 8" joists. The span of the joists is 5.5m.
My tiler/plumber has started using this existing 11m ply (which is porbably not WBP ply) for the overboarding. So floorboards + ply is total about 40mm. He says he's going to screw it down very well so it won't move. Indeed I can't feel any movement.
I'm happy to go with this if: (1) he screws both floorboards and ply really well, (2) flexi adhesive of course and (3) *maybe* add ditra matting in case of small movements over time.
edit: Worth noting the shower tray is 1.2x0.8 so might be used by a couple at the same time
1. Will this be ok long-term? (The job is already well underway, so if I force him to change to e.g. 18mm WBP ply I'd have to explain why I'm insisting.).
2. Is the ditra matting a must in this instance? The reused 11m ply is presumably not WBP, but will a ditra mat also provide moisture protection to the ply? (There's no pipework in the floor except the waste from a sink and shower).
3. If the 11m ply + ditra is too risky, what's the lowest-hassle way of improving this? (6mm backerboard on top of the 11m ply?)
amny thanks,
Ash
