Ceramic tiles on wooden floor

[mdrandall]

I'm sure this question has been asked but searching thru' the threads hasn't shown up exactly my situation.

I have a brand new house with the upstairs floors made of the thick (1"?) compressed green boards that lock together. I am planning to lay ceramic tiles (poss tumbled marble) in the bathrooms and would like some advice on the floor preparation.

I have seen suggestions that the floor should be reinforced with 12mm WBP plywood. However, this combined with 3mm for electric heating mats, another 3mm for flexible adhesive and then 10mm for the tiles makes this much too high.

How important is the plywood on my floor?

Would 6mm plywood be enough?

Maybe using flexible adhesive/grout directly onto the green boards would work OK as a "professional" fitter just did in a neighbours house?

Thanks for any advice..........................

 

[masona]

I have a brand new house with the upstairs floors made of the thick (1"?) compressed green boards that lock together.

Has it got Graded P5 stamp on it somewhere? If so that would be the green T&G moisture resistant board.

I have seen suggestions that the floor should be reinforced with 12mm WBP plywood. However, this combined with 3mm for electric heating mats, another 3mm for flexible adhesive and then 10mm for the tiles makes this much too high.

How important is the plywood on my floor?

Would 6mm plywood be enough?

Chipboard if that what I think you may have won't really be any good specially with heating mat, I would rip the flooring up and renew with 19mm (3/4") exterior plywood with non-rust screws and this would also give you the same level as the flooring. If you want to go lower I suppose nothing can stop you using 12mm thickness plywood but will need a lot of extra noggins to prevent spring action.