QUESTION

Hi. I am a homeowner and I got a full kitchen renovation done less than 2 years ago.

When my contractor was tiling, he tiled 12x24 porcelain tiles directly on the plywood/subfloor. I know that wood needs to breathe and gluing big tiles directly on top of the plywood didn’t make any sense to me. I asked the contractor if that was okay and he assured me that it was fine. About 4 months after the renovation, the grout on high traffic areas started cracking. Now, I can even see the tiles moving up and down and lose grouts are coming out everyday.

I found 2 contractors who are willing to fix my kitchen.
1st contractor wants to do everything from scratch. Take all the base cabinets out (whole kitchen floor is tiled) and retile with cement board.
2nd contractor wants to cut out the tiles only in the visible areas and use wire mesh on the plywood.

I have 2 questions for you.
1. Do I have a case against the original contractor for faulty installation?
2. Should I have the whole floor retiled with cement board or just visible areas with wire mesh?

I want everything done right the 2nd time. It would be awesome if I can get an advice from an expert!

ANSWER

ANSWER - It is acceptable per the industry standards to adhere tile to a wood subfloor in dry applications.   The plywood subfloor should have a plywood underlayment over it and the configuration of the floor and underlying structure needs to be such that there is not excessive deflection in the floor, which for ceramic tile is not more than L/360 deflection.   There are industry standards that give guidelines for these types of installations such as TCNA F142-15 or F160-15.  It sounds like your floor might have excessive defection and that may be why the grout has started cracking.  Generally speaking when there is a problem it isn’t due to only one deficiency but there may be multiple compounding deficiencies.   Depending on the circumstances, the installer could be liable for the problem.

If you don’t understand what the problem is then you risk the problem reoccurring or other problems can occur.

The first thing is the wood subfloor configuration needs to be evaluated to determine if it doesn’t exceed the L/360 requirements for deflection.  You may need a structural engineer to evaluated it.  They can add bracing or additional joists to the floor to make it more sturdy.

I don’t think it is necessary to remove the cabinets.  You need to leave a joint between the tile and the cabinets and fill it with an ASTM C920 silicone sealant.

If the wood subfloor is flat then the cement board is ok to use if it is installed correctly by staggering them, glue and screw them down, and filling and taping the joints per the cement boards’ manufacturer’s directions.

Putting building paper with metal lath mesh over that and then applying a mortar to level and flatten the floor is ok too if it is done correctly.

If it isn’t practical to hire a company like CTaSC to write the specifications and provide quality control services during the installation to help ensure a successful installation, then download our free Installation Guidelines for you to follow as the home owner and be the quality control person to help make sure it is a successful installation.  Click here for Free Installation Guidelines.