Grout has stained lueders limestone
Q. We had a new lueders limestone fireplace surround installed. There are darker stripes on each side of all grout lines. Installer said grout was not acrylic, but grout did have some colorant. Stone has dried now three weeks and stains still present. What is cause, and how can stains be removed?
A. This is a common problem with some limestones. Certain grouts will bleed in. The first thing you need to do is make sure that it is dry. (I have seen some installations take months to dry.)
The best way to determine what the problem is is to take a hair dryer to the dark areas and see if you can dry them out. If not then it is stained. It is possible to remove the stain by using a poultice or a stain sponge. I would first test a small area. You may have to have the grout removed before applying the sponge or poultice.