When laying floor tile on a bare plywood floor do I have to put down wonderboard?

Question

Essentially do I have to put down any kind of material before the floor tile is down. Can I put floor tile on bare plywood?

Answer 1

Typically, Yes, you need to provide some kind of underlayment.

You failed to specify which type of tile you are asking about... details matter.

Ceramic Tile -- plywood flexes too much for ceramic tile.... if you lay ceramic tile directly on the plywood sub-floor, you should expect to be replacing it fairly soon.

Vinyl Tile -- typical plywood subfloors are not smooth enough for vinyl products. Subfloor plywood usually has voids in the surface, gaps between the seams, sometimes even an extra piece of wood is stuck to the surface. All of this will telegraph thru any vinyl product, whether it is commercial grade tile, or rolled goods. You should install a luan (loo-awn) underlayment. This is usually a mahogany veneery ply, 1/8" to 1/4" approximately. Screw the luan underlayment in place, then fill the seams, and screw heads with something like DuraRock filler, or a cement type floor filler.

Now, if you use a 'laminated' floor product... whether it has a high pressure laminate surface (i.e. Pergo flooring), or a wood veneer surface, you can usually get away with just a heavy felt, or foam underlayment. (Always use a moisture barrier, when placing this type of product over concrete). Make sure you use the approved underlayment for whatever choice made here, because it WILL affect your warranty, hehehe.

Have Fun!

Answer 2

Yes you can do whatever you want. However if you don't want it to crack and come up soon I would use the cement backer board. The backer board hasn't been around that many years so you know it was put over plywood before. It's just a matter of how often you want to replace it on whether or not to use the newest technology to make it last longer.

Answer 3

I assume that you are talking about ceramic tile. If so, then yes an underlayment must be used. A better material is Hardi Backer. See http://www.jameshardieeu.com/downloads/hbacker_instinstr_01_en.pdf for installation methods.