Dear Andrew:
Have you ever heard the expression, “wrong stone for the job”?
I guess I don't need to explain what it means, do I?...
Many sandstone (actually most of them), are not suitable for a project like yours, and no miracle in a bottle could ever do the first thing to turn the wrong stone into the right one. You may get an apparent improvement, but soon the ruthless truth will come to the surface.
And, BTW, as a good solid principle, you should never apply an impregnating sealer or any other sealer to outdoor stone installations. Even stones that are suitable for outdoors may develop problems if their natural osmosis gets somehow slowed down by an impregnator.
Ciao and good luck,
Article ID: 17
Created On: Tue, May 8, 2007 at 8:17 AM
Last Updated On: Tue, May 8, 2007 at 12:00 AM
Authored by: Maurizio Bertoli [mail@mbstone.com]
Online URL: https://marblecleaning.org/knowledgebase/article.php?id=17