Radon sealants - need advice...

mikey553February 17, 2008

I am planning to organize a machine shop and a workout area downstairs, however the radon level there is around 12. In the living area on the first floor it is around 5. I do not want to die before my time so I am trying to fix that.

After sealing the gap between the concrete slab and the block walls the level in the basement dropped to 6. The floor is bare but the walls are painted with Drylock and latex topcoat. I still have a few gaps to seal, but am afraid it will not bring me to my goal. Radon still can seep through the floor and the walls.

Since I am not too keen on the fan-based radon mitigation, I would like to try concrete sealants on the floor, and, possibly, on the walls. RadonSeal.com has many happy customer testimonials, but I wonder if company is telling the truth. This product is a silicate and it is not cheap. There are other similar products on the market like X-1 from Stone Technologies, CP-1007 from Chemical Products Industries and some others.

I would like to hear if any of you has used these products and what was the outcome. Thanks in advance for sharing!


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I used a product called radon seal. Sprayed the walls and floor. I have not tested it. I only did it to be safe. Check this web site. Its a spray on app.

Here is a link that might be useful: radonseal

    Bookmark   February 20, 2008 at 1:31PM
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I used radon seal on my basement floor and walls, followed by Drylok on the walls and a latex floor paint on the floor. This was in addition to sealing the gap around the slab. After all that the Radon reading went from about 6 to about 1. I didn't test at each step, so I can't say for sure how much each step helped.

The Radonseal web site is a bit overstated I think, but when I researched this, I couldn't find any complaints about the company. The product soaks right in to the concrete and leaves no visible residue on the surface. I also let some dry up in a jar to see what was left, and there was a clear crystalline residue (quite a bit compared to the amount of liquid I put in the jar), obviously the silicate compound. Given those two observations, it seems to me that the silicate must do something to clog up the pores in the concrete. In other words, the silicate goes into the concrete as a solution, and doesn't come out, so the crystals that form must be taking up pore space, but to what extent, I can't say.

I can confirm that it has no odor, and feels like water that has a little soap in it.


    Bookmark   February 27, 2008 at 11:38PM
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Thank you, Alex and Mike. The only reason I am asking about alternatives to RadonSeal is that they are significantly cheaper.
CP-1007 is potassium silicate and X-1 is sodium silicate blends. RadonSeal does not provide any details, saying only that it is a silicate based sealer. Is there any difference in performance? Who knows...
Had anybody else used similar products in the past? What was the result?

    Bookmark   February 29, 2008 at 5:47PM
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