QUESTIONHello, our limestone slab fireplace was installed in July 2017. Since installation we have dark stains where the seams are on the limestone. The installer says they will go away in time but it has been 6 months and still no improvement. Is this to be expected? Is there anything we can do to remove it?
ANSWERANSWER - If you have dark stains at the seams of the limestone fireplace, that suggests that the stone installer used a sealant or resin for those joints that bleed into the stone leaving a stain. This is a condition that isn't likely going to go away. Some sealants or resins can stain natural stone, so the installer has to make sure what they use is compatible with the stone.
You can hire a professional stone restoration company to come out and redo the seams. They might be able to remove the stains using a poultice or by grinding and re-polishing the stone.