QUESTION

Why is my grout soft and coming loose in my ceramic tile? - My homebuilder layed my ceramic tile with no spacers and an extremely small grout line. The grout space runs 1/8" or smaller, but again, varies. All grout in my house has been replaced several times and still does not harden. The grout is like sand and can be scraped with your finger. Sanded and non-sanded grout has been used. The grout manufacturer has also been contacted and the brand has been changed. I've also been told it could be my water and the builder has brought out their own source of water, but the results are the same. "PLEASE" provide your advice!

ANSWER

ANSWER - Your grout should not be coming loose and not hardening.  It sounds like your grout joints might be too narrow to easily allow the grout to fill it.  Depending on the type of tile you have it generally requires at least a 1/8" or 3/16" grout joint.  Based on you saying the grout joint width varies, it likely should be the 3/16" or larger.  The more the tile variations in dimensions and warpage the larger the grout joint should be.

Normally when there is a problem it is not due to one deficiency, but is normally due to many compounding problems.  The grout joint may be too narrow not allowing the grout to easily fully fill the joint, the installer may not be properly compacting the grout in the joints, the installer might be making the grout too wet and using too much water during the clean-up causing the grout to be weak (considering you said the grout could easily be scraped out with your finger, and you have used different grouts with the same problem using the same installer, this could be a clue...), there might be too much movement (deflection) within the floor, and there may not be proper movement joints within the tile work to relief the tile from the various stresses.

To determine the cause of your problem would require an intrusive inspection and perhaps some laboratory testing, which is not likely practical for you to do in your case.  I would replace the installer with an experience tile installer and make sure they precisely follow the grout manufacturer's installation instructions.  We do have inspectors in Texas if you need our services.  For more information on our investigation services go to www.CTaSC.com.  Good Luck.