Decoupling membrane over ply

[linton1990]

I know this kind of thing comes up all the time, but i cant find anywhere for this. In my kitchen i have a 16mm floorboard floor. When i tile bathrooms i remove the floor, board with 18mm ply, board with 9mm and durables the lot. My question is, i cant remove the floor and height is an issue due to a range cooker being level with worktops. So would it be ok to still board with 9mm ply and then membrane. Or would i be best to board with 12mm and not worry about the decoupling? Thanks in advanced

 

[LM]

I know this kind of thing comes up all the time, but i cant find anywhere for this. In my kitchen i have a 16mm floorboard floor. When i tile bathrooms i remove the floor, board with 18mm ply, board with 9mm and durables the lot. My question is, i cant remove the floor and height is an issue due to a range cooker being level with worktops. So would it be ok to still board with 9mm ply and then membrane. Or would i be best to board with 12mm and not worry about the decoupling? Thanks in advanced

I can’t quite understand exactly what you mean.

 

[LM]

Whatever you do make sure your floor is deflection free and structurally sound and if it’s on top of wood make sure it’s decoupled.

 

[linton1990]

The floor is very sound. Sorry my question being, if i boarded with 12mm could i not bother with the membrane? Or would i be best to go with the 9mm ply and membrane.

 

[LM]

Providing your joist spacings are adequate 18mm structural ply (tounge and grooved) will suffice but 22mm is better, with direct uncoupling on top.
It doesn’t matter what thickness of overboarding you use, if it’s wood you will still have to uncouple. So long as the floor is stable and deflection free, if you decouple it it will be fine.
There is no excuse nowadays for tiling on plywood when there are so many options available that are far superior and competively priced.