I have a stone foundation in my basement which was re-pointed about 4 years ago.

While slight, the mortar crumbles a little bit over time. As a result, it causes a bit of a mess with the dust at the edge of the flooring.

I would like to seal or coat the stones and mortar so that crumbling stops. I don't want to paint the stones, just seal or coat them with something clear. Any suggestions on what kind of product to use to do this?

I was thinking of using something like this: http://www.homedepot.com/p/Seal-Krete-1-gal-Original-Waterproofing-Sealer-100001/100144884

However, I am unsure if that would be effective or cause any problems with the stone and mortar wall. In addition, I am located in Canada and the Home Depot in Canada does not seem to carry this product.


  • Two concerns: a) it's tough to truly stabilize crumbly mortar/concrete/brick, and b) you'll never be able to change your mind on the sealer. Mar 30, 2016 at 0:07

1 Answer 1


I'd recommend using pure sodium silicate or potassium silicate for this. These chemicals will form a waterproof seal that is breathable, preventing moisture from becoming trapped and deteriorating the mortar over time. In addition, they will chemically bond to the mortar and actually strengthen it by introducing soluble silica, sealing the micro-pores in the mortar and reducing alkali-silica reactions and efflorescence. Highly recommended. Here's an example product that you can get on Amazon (no affiliation): http://smile.amazon.com/Rutland-146-Cement-Sealer-Fireplace/dp/B004YEDQOK

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