Posted by MikeC on December 14, 1999 at 17:26:56:
In Reply to: Soft subfloors posted by Lisa on December 14, 1999 at 07:51:52:
: HELP! I'm having a problem with a subfloor which is set on trusses 24" apart. While they are within code they are not providing the support needed for ceramic tile. Grout is cracking. Any suggestions on how to "stiffen" the floor so I can successfully install ceramic without the grout and/or tile cracking? The attempts made have so far been unsuccessful. Will wonderboard make a firm enough foundation to prevent movement of the tiles and grout?
Sounds like a condo.
Is the tile currently adhered directly to the subfloor? If it is, that's your problem.
If not, check the thickness of your subfloor by popping out a heat register in the floor.
Anything other than 3/4" CDX plywood for a substrate of your type and you may have a problem. 3/4" OSB board ( chip board) is pushing the envelope.
But in a nut shell...Either the ceramic tile was installed wrong, the subfloor is too thin for the 24" expansion or something is wrong with the truss system. The ceramic was probably installed wrong.
Find out wich one it is, then correct the problem.
If this is a D.Y.I. project, you may be able to get away with 1/2" wonder board if you install it correctly but the best way to do it is to have the floor mudded by a tile contractor.
Mike
Universal Floor Company