QUESTIONCeramic Tile Warpage - We just bought over 90 square meters of porcelain tiles (gres) of top quality (prima scelta) at a price of around 40 euro per square meter. When we started installing them we found out that they are not completely flat (if you put them face to face you can see a tiny ray of light through the center). When we contacted the manufacturer they said that that is the way the tiles are. Is it possible if they are top quality? I think that we were given second choice tiles at the price of top quality ones. Thanks.
ANSWERANSWER - There are ANSI A137.1 industry standards on quantifying what is considered acceptable dimension variation within standard grade ceramic tiles. Ceramic tile is not perfect and the installation methods help compensate for the imperfections to some degree.
Your description of warpage may or may not be considered excessive. I normally would expect porcelain tiles to fit flat to each other.
We have seen where the tile might meet the maximum allowable warpage, but it is all concentrated within a short span of the tile edge. Even though the industry standards do not currently address this condition, I consider it not acceptable.
If it were worth the investment, the tiles could be tested and an investigation could be conducted, and a report written.