limestone tile flooring and sealing

Q. I have recently installed 12 x 12 limestone floor tile. It's extremely porous more like sandstone than traditional limestone. Once sealed, the grout began to bleed into the tile and create a hazy frame around the edges of most tiles. My tile sub contractor has attempted to sand away the suspected grout residue only to discover that is goes all the way through the tile. Today, I heard that the tile should have been sealed prior to installation and grouting. Is there anyway to remedy this other than tearing it out and starting over? And, is it a typical procedure to seal all limestone, or porous stone, prior to installation? Your help is greatly appreciated.

 

A. It is possible to use a poultice but honestly it might not work, depending on the type of grout used. It is recommended to seal the stone prior to grouting to prevent this from happening.

 

Dr. Fred
www.stoneforensics.com