Here are some pictures of a porcelain floor at a commercial location that was grouted with a polyurathane grout. Dark sanded grouts are challenging to install anyway due to the clean up so problems like this are not uncommon. Polyurethane and epoxy grouts can be a real nightmare.
We had use a honing powder to remove the grout haze from the tiles. The darker tiles have the grout haze or film on it, and the lighter tiles have been honed to remove it.
Color sealing is the best alternative. Installer can use a regular sanded grout, which is more cost effective and the color seal protects the grout against staining and efflorescence. I’ll discuss efflorescence in my next post.
