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.

I used radonseals other formula called LatisSeal on the cracks in my basement floor. It worked like a charm and there is no more rain coming in through them. Did not use it for any radon coming in just the water.

I use only 1 product to seal and patch basement walls and floors, Hydro-Seal 75 manufactured by Northern Industries. This material is a 1 to 1 waterbase epoxy coating that applies like paint with 1/2" or 3/8" nap rollers to both walls and floors in a nice pigmented finish. I use the gray or light gray almost always because I always apply to the walls and floor perimeter. The kicker is that I mix dry cement and sand into the Hydro-Seal 75 to create a patching mortar for cracks, the floor joint and anywhere else I need to patch. I never could find any waterproofing testing data on the Radon Seal, but Hydro-Seal 75 is tested to 40PSI. Plus it is economical, fast drying, odorless, and puts a beautiful finish on ugly stained basement walls covering up and restoring even the worst stone & mortar foundation. Thats something a clear coating cannot do. In my opinion the best radon sealer is the best waterproofer, and crack filling counts.

The Hydro seal 75 sounded great based on your post about the best water sealer should be the best radon sealer however I noticed that one of the qualities that makes hydro seal a good water sealer is that it "allows vapor transmission."
Would that then mean that it allows transmission of radon vapor/gas??

I was actually going to go with RadonSeal but ended up going with Foundation Armor. The thing that made me switch was the customer service, Foundation Armor had amazing customer service. Call me an advocate now but I have never worked with a product that works as great as Foundation Armor. I had very bad seepage coming through my basement wall. I applied three coats of their L3000 sealer and not only did it stop the water after about 6 hours but when Hurricane Sandy came through I never had any water issues. I am a true supporter of Foundation Armor and use them now for all of my jobs. I would consider doing your own comparison of the two companies.

I have a 59 year old house and there was a mold problem.....years ago the interior foundation wall was painted and the insulation and drywall installed over it. The insulation job was very poor and allowed for air spaces directly on the foundation wall. Mold grew. I had to gut everything and remediate mold. I had the foundation wall sandblasted to ground level. I had concerns about mold and moisture through the foundation wall returning if I re-insulate and drywall. I used radonseal. I applied it as per the instructions with 2 coats. After applying it I had a new odor in the vasement. Smelt like a musty, algae, damp cement smell. Rodoseal is supposed to be odorless and the distributor said heès never had anyone call about an ador after applicvation. I waited 3 days and the odor subsided somewhat but was still there. I remained concerned about reviving dormant (dry condition without food or moisture)mold and mildew or it being pushed out from deeper pores as the radonseal cured. I applied microban QGC and mold and mildew killer that is also a deoderizer. QGC is concentrated and is mixed with water. When I sprayed the mixed QGC on the wall with the pump sprayer It absorbed into the cement. I was surprised because I thought the radonseal would act as a sealer and most of the QGC would run off but it didn't. I call Rodonseal about it and they said the radon seal works deep into the cement poors so may be still somewhat porous on the surface. I dunno....I'm sceptacle now whether radon seal works. I'll see if the smell goes away now after using the microban QGC. I do know that mineral silicate sealers which I think what radonseal is....cannot freeze or it will ruin the product. So if transporting this to the distributors in freezing conditions.....who knows what faulty product you might get.

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Our house is 100 years old, the basement walls were constructed of both concrete block and poured concrete. We were having flooding in the basement when we would have large amounts of rain. After installing a interior perimeter drain system and sump pump, I started prepping the walls to be painted. In the course of the preparation I discovered that the moisture in the concrete block had caused the paint to separate from the wall. While the paint looked fine if you tried scraping it several layers of paint would come off. After discussing the problem with Radonseal customer service, I stripped the walls down to bare concrete used RadonSeal Plus and Ion Bond Armour to seal the walls. The Ion Bond was used to go through the fibercrete used to repair areas of the wall that had deteriorated. In the areas that were treated both products have worked very well. The concrete block has remained completely dry through the spring rains this year, now I can paint the walls. While not cheap, both products work very well which in the end is worth the cost.

I noticed that RadonSeal dilutes their silicates and sells low solids products. RadonSeal also appears to have poor customer service and ignores phone calls. I went with Foundation Armor because they sell commercial grade products and were willing to run me through the application process as many times as I needed.

So what are we concluding? I see a lot of indication that customer service is poor. That problems are called the result of bad application. Apparently Radon Seal dilutes their scilicates - the blocking agents. There is a question as to whether a good water sealant, which is vapor permeable can also serve well as a radon block, since radon is a vapor.
...HELP! Should we use Radon Seal or not?

Radonseal worked great on my basement. I did not have a radon issue but the walls were moldy and leeching efflorescence before. I followed the directions, stripped the old paint off the walls, washed, and used 2 coats of RadonSeal Plus on the concrete block walls and 2 coats regular Radonseal on the newly poured concrete floor. The basement really dried up, it was a noticeable improvement, almost like the first floor above grade. It stopped the efflorescence also and seemed to do what it claims.

I have never experienced concrete dusting here in Utah except for faulty for concrete application so, I assume faulty concrete, however, I see many comments about dusty concrete when researching this product.

Decision:
I am still unsure about whether or not to try RadonSeal. So far, I'm left feeling the company lacks integrity with their warranty claims (just like many car dealers) and therefore their claims may not be legitimate.

Solids and Penetration:
More, or larger solids would not penetrate as deep so a thinner product would penetrate deeper. Surface sealers, like paint, are more likely to peel or bubble and fail which is why you can't just paint the walls.

Preparation:
The main take away for Radon mitigation is complete sealing/patching every nook and cranny, then applying a sealer and also ventilation.

Surface Sealing and Ventilation:
RadonSealer says it's "deep penetrating" for a deeper overall seal. Most concrete sealers state they are ventilating because "trapping" water can be problematic in some applications but for radon, it seems you want more sealing than ventilation. Modern waterproof jackets are ventilating yet still waterproof.

For anyone using the foundation armor, how did hold up? Do you still recommend it?

Radon seal is Sodium Silicate. 175 dollars for 5 gallons diluted.
Rutland makes “water glass cement floor sealer”. It is concentrated sodium silicate you add 4 gallons of water to make 5 gallons to apply to concrete. Cost? 27 bucks. Radonseal might have a carrier ingredient but I am sure the sodium silicate is what “seals” internally in the concrete.

lots of salesmen from different companies showing up here to provide "insight". Who let those Floundation Armor hacks in? those guys were selling underpants on Amazon a couple years ago. now they are concrete experts? lol. nothing to learn here. moving on.

WHen buying online, you need to look at the how long the company has been around. also check the BBB rating.

Many concrete sealers found online are pop-up stores reselling other products. Check the technical data sheets on products form Foundation Armor and Concrete Sealers USA. they are identical. I asked the fella from Concrete Sealers USA about it. He told me that they supply the product to Foundation Armor. Same stuff....different wrapper.

Look at the company history. It will tell you more than you think.

Used RadonSealer on my cinder block foundation. Had to remove the paint before applying the sealer. That was tough work. So far, so good on my basement. I applied around october of last year.

My home is older 100+ and the basement is stone and brick. Will concrete sealer work on that?

@BV018248, your foundation walls sound similar to mine: stone & rubble & porous old mortar. One coat of HydroSeal (mentioned earlier) and I never saw another drop.

That was five years ago. I never got around to the second coat we'd planned, but I do intend to treat that floor.

Great service, by the way: small company, and you can get thoughtful advice from senior people there.

@BV018248 .... Penetrating type sealers will not work on natural stone - too dense. Proper repair would involve grinding out the old mortar joints and repointing. Once the mortar has cured, I would recommend a sealer called LastiSeal. Frankly, the best sealer Ive ever used. Never use silane, siloxane, acrylic, or lithium sealers below grade. They are for driveways and patios.

I used RadonSeal PLUS and IonBond Armor to get the moisture transmission levels low enough to install wood flooring in a 10,000 sq.ft office lobby area. We had soo many floor "experts" in the shop but each time a new floor was installed, it warped and peeled in a matter of months. I spoke to RadonSeal and they provided a 70-year written warranty that the moisture rating would not exceed 5lbs. Other companies laughed when i asked for something in writing. that was two years ago. Happy to report no problems so far. .... fingers crossed!

that should read "7-year" not "70-year".

check out the reviews for RadonSeal (BBB, TrustPilot, etc..). They been in business for literally decades.

Not like these pop-up sealer distributors. The sealer world is a small one. Most of the these guys are resellers. For example, Foundation Armor gets their products for Concrete Sealers, USA. They just dilute them a bit to make their margin, add their own label, and voila!

You really need to look into companies these days. Its hard to know who is legit.