I am also trying to research this product and wonder if it really works. If anyone has tried it, I would like to know about their experience as far as its radon mitigation effectiveness. I am leary of the so-called "testimonials" on their own website.

I have never tried that product but have used what seems to be a similar product with positive results. Addressing cracks is the most important aspect of lowering radon in a basement. Radon levels above the 4pCi/L are considered dangerous. However if you are a smoker, your risks of being affected increase dramatically. Ventilation of the basement would be most beneficial. You also may want to check your water supply for radon levels.

If you do decide to try that product, make sure you prepare the surfaces by removing all dust/dirt from the pores of the concrete. Surface prep is key with any product you use on concrete. I highly doubt RadonSeal will warranty their product because there are so variables on why their product failed with all the fingers pointing to application error.

Maybe someone will decide to call them with a warranty issue to document their response.

There seems to be information out there that these types of radon sealants wear off over time? At least that's what the EPA seems to say.

See link here:

http://radonblog.buggyinfo.com/radon-loc-and-radonseal-do-they-work/

There is a comment below the main article that has a link to an EPA statement

What levels are you guys at? Mine is very high (45.8) so I'm wondering whether even if this stuff works it will do what I need.

I bought this as a waterproofer as they also advertise it as that.

Followed the instructions to the letter and after the first decent rain (1/2 inch) my cement blocks were wet again. I figure if it will let water through, there is no way it is stopping a gas from coming through. I contacted the company about this and never heard back. Could have done better by gluing 200 - $1 bills to the wall.

Did you use the RadonSeal PLUS product, and did you apply 4 or coats to refusal?

I have heard similar complaints where the company does not stand behind their product and if you have a failure, it is always application error. This is common with a lot of other products sold on the internet.

Surprised to see negative comments on RadonSeal. I've used it on three properties successfully. In one case, i didnt see a significant drop in radon levels. After some research, I decided to patch my floor to wall joint...and BAM. less than 2pc/L on my radon detector.

I had concrete dusting and dampness that would not go away (3 years old concrete). Always sweeping or using shop vac to clean floor. dust always returned!!!!!! Tried washing too. I have been told that I have faulty concrete?? Is this true???? Applied radonseal to walls and saw huge improvement. Very little to any dustiing at all since I applied (2/10). Basement has stayed dry. Working for me.