Do RadonSeal waterproofing products work?

Question: We are purchasing a 100 yr old home in Oakland with a concrete floor in the basement, which we would like to grind, stain, and seal. We don't know if there is a vapor barrier under the concrete.

We learned about waterproofing sealers made by Radon Seal. They claim that their penetrating product bonds with elements in the concrete to seal out water, both surface water and negative pressure moisture from under the concrete.

Their site contains lots of testimonials from happy customers who have solved damp basement problems with their sealers. Is this product a valid vapor barrier?

Answer: Full disclosure, I am an affiliate with Radonseal, they pay me a commission when you click through to their site from mine and purchase a product.

Having said that, I use their products in my business, Day's Concrete Floors, Inc. because they work very good.

Their sealers do block a certain amount of moisture from the sub-base from coming up through the concrete. But like any moisture mitigation product, they are only rated for blocking a certain amount of moisture.

If you just have a damp, musty smell in the basement, then you should be just fine using Radonseal's sealer. If you have water coming up through the floor and puddling on surface then you have more moisture than a sealer will block.

Radonseal has Calcium chloride test kits to test the amount of moisture vapor emissions coming up through a concrete floor. This is an easy test to do before you grind and seal the concrete.

To stain and seal the concrete after you grind it you could use their product called Lastiseal. Lastiseal comes in many different colors, is water-based (no odor), is easily applied with a fine tip pump up sprayer and will block moisture.

I have used this product many times to stain concrete floors with excellent results.

So to simply answer your question, "is this product a valid vapor barrier" I would say yes, it will block moisture vapor as long as it's not excessive.