Fixing plywood on ???? Help, advice, information, answers and tips on all types of flooring from laminate and carpet to timber and vinyl

[JossiH]

I have a balcony that I want to tile. The floor is covered with this rubber material that is glued onto a plastic sheet of some sort, probably some kind of insulating material, and I think there is foam underneath that.

I am not sure what the material is. Can I put plywood on top of that? Is there an adhesive strong enough to fix the plywood and make it solid?

I wish I knew what the material was. Please help me!

[molsen]

It depends upon what you are going to lay on top of it. If you are tiling ceramics, quarry etc then you will need to screw the plywood down firmly, ensuring that the screws are countersunk into the wood. To prevent any movement at all, you should ensure that the screws go into the joists underneath the floor.

Most tile cements nowadays have a good degree of flexibility built into them, but you can buy an additive for greater flexibility. However the best way of course would be remove all of the material then lay the plywood directly onto the floorboards. It will save you a lot of grief - if the surface isnt absolutely flush and flat, you may regret it.