QUESTION

Subfloor Cracks - What can I do to prevent cracks in subfloor to continue through my ceramic tile or stone?

ANSWER

ANSWER - To keep it simple, there are two basic types of cracks. A structural crack that moves vertically or a shrinkage crack that moves horizontally. You can not treat a structural crack. You either intentionally continue it up through the ceramic tile or stone or there has to be a major epoxy repair with dowel pins. You need an engineer to prescribe the solution. You can treat a shrinkage crack by installing an anti-fracture membrane (also referred to as crack suppression membrane).

The membranes are available in several forms which are trowelable, liquid applied, peel and stick, or a sheet membrane. There are several quality products on the market, so contact your local distributor to give you a recommendation. For links to installation manufactuers go to Industry Resources and Links section of this web site.

Check the manufacturer's warranty to make sure you comply! The way they work is that you attach the membrane to the concrete substrate. Either isolating the individual cracks by centering and covering at least three times the width of the tile you are using. Or by covering the whole substrate to have protection in case cracks develop later. Then you thin-set your tile to the membrane. Be sure to follow manufacturer's instructions.
ANSWER - To keep it simple, there are two basic types of cracks. A structural crack that moves vertically or a shrinkage crack that moves horizontally. You can not treat a structural crack. You either intentionally continue it up through the ceramic tile or stone or there has to be a major epoxy repair with dowel pins. You need an engineer to prescribe the solution. You can treat a shrinkage crack by installing an anti-fracture membrane (also referred to as crack suppression membrane).

The membranes are available in several forms which are trowelable, liquid applied, peel and stick, or a sheet membrane. There are several quality products on the market, so contact your local distributor to give you a recommendation. For links to installation manufactuers go to Industry Resources and Links section of this web site.

Check the manufacturer's warranty to make sure you comply! The way they work is that you attach the membrane to the concrete substrate. Either isolating the individual cracks by centering and covering at least three times the width of the tile you are using. Or by covering the whole substrate to have protection in case cracks develop later. Then you thin-set your tile to the membrane. Be sure to follow manufacturer's instructions.