Section of Newly Installed Stone Is Darker Than Surrounding Stone

Q. Natural stone tile installation has water marks that aren’t fading after 2 weeks of installation. Should I apply a poultice to remove the moisture? MSI sells the stone. It's called white oak. It's honed marble, 24 inch tiles, and the installer used white mud to install it. I want to avoid tearing the whole thing up and having it reinstalled.

A. The dark appearance of the stone is likely due to moisture. Use a blow dryer on the stone to see if it lightens up at all. If it doesn't, then the problem may not be moisture after all, but a problem with the mortar. Wait a few weeks before tearing it out, though, just in case it is a moisture problem that needs more time to dry out. Keep the area as moisture free as possible. If you notice the color of the stone lighten at all, then it will continue to lighten and the problem will eventually resolve itself. If the stone does not lighten at all, then it will need to be replaced. Using a poultice on the stone will not resolve the problem. Poultices often leave stone looking a little darker, because the stone absorbs some of the moisture in the poultice. In other words, the poultice will not draw the moisture from the stone.