My basement had multiple cracks (no comments about my builder's skills). This product stopped leaks completely. Now I can install drywall. I bought the crack repair kit on Amazon, but I needed more co... See more
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A reasonable and helpful company. They answered questions, and assisted finding right product. The product isn't cheap, not expensive either, but works as it should. They provide plenty of documenta... See more
The customer service over the phone was amazing. The gentleman I talked to walked me through all the products I had questions on for 45min. He did not try to upsale me and even talked me out of one of... See more
Company replied
Fantastic product and support. Especially happy with Mike, who patiently answered my questions on multiple occasions and helped me find the right product for my project. The concrete sealant for my... See more
Company details
Written by the company
It happens to thousands of homeowners each year – the sale of their home falls through because of high radon in their basement. They have to hustle to get a radon mitigation system installed and hope that the buyer will not walk away. But for many years after, they may wonder about the long-term effects of the radioactive gas on their children. Since radon gas seeps into basements from the ground, the US Environment Protection Agency had tested the obvious solutions back in the 1980's – caulking all cracks and sealing the concrete with various coatings but the improvements were not significant or lasting. Thus, the fan-based system which draws soil gases from underneath basement slabs became the standard. There had to be a better way! Novion Inc. was founded in 1987 to pursue innovative high-tech solutions. Penetrating concrete sealers, already well-proven for waterproofing concrete on major projects, seal concrete internally and permanently. Perhaps, they could be improved to penetrate deeper and seal even tighter to keep out the single-atom radon gas. After extensive research and testing, the first concrete sealer specifically developed to reduce radon infiltration through concrete was ready for the big debut – RadonSeal® Deep-Penetrating Concrete Sealer. Novion Inc. was incorporated in Connecticut and RadonSeal was made available directly to homeowners and contractors on radonseal.com website. Subsequently, we have continued to add unique innovative products, not available in stores, for basements, indoor or outdoor concrete, bricks, pavers, and masonry. Going beyond radon remediation, we provide durable and cost-effective solutions for waterproofing basements, sealing concrete slabs against vapor, and mold remediation. Our products also protect and beautify indoor or outdoor concrete, pavers, and masonry. Our mission is to supply cutting-edge, professional-grade, and environment-friendly products, superior to those sold in stores. Our customer support offers technical expertise and objective guidance on the best solutions for customers' needs. Whether you are a homeowner, contractor, or building owner, we will provide the top-quality products and service to solve or prevent problems with your basement, parking lot, pool deck, brick or masonry walls. It can be just a matter of time before your basement or outdoor concrete starts giving you problems. Act now and give us a call. We are here to help!
Written by the company
Contact info
494 Bridgeport Ave, Ste 101336, 06484-4748, Shelton, United States
- 203 225-0366
- admin@radonseal.com
- radonseal.com
4.6
Excellent
2K reviews
Asks customers to review
This company invites their customers to review, whether positive or negative
Replied to 36% of negative reviews
Typically replies within 24 hours
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Great customer service and prompt when…
Great customer service and prompt when taking my order!
February 9, 2026
Reply from RadonSeal
Thank you for the kind words!
Providing responsive, reliable support is very important to us, and we truly appreciate your feedback and your business.
Kind Regards,
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Customer Support
RadonSeal
Well run company
Website is easy to navigate, good descriptions of the product, payment went smoothly.
February 6, 2026
Reply from RadonSeal
Thank you for your feedback!
Please let us know if you need any assistance.
Kind Regards,
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Customer Support
RadonSeal
Easy ordering
Easy ordering, fast confirmation and invoice, and clear email shipping updates. Smooth experience.
December 18, 2025
Unprompted review
Reply from RadonSeal
Thank you for taking the time to make a review.
If you ever experience any difficulty while ordering online, please don’t hesitate to reach out. Our team is always happy to assist.
Kind Regards,
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Customer Support
RadonSeal
More than helpful
More than helpful! I had to email them quite a few times with questions, and they never once made me feel like I was a bother. They were most helpful and assisted me with purchasing the right product for my project. My package came in today and could not be more pleased with the speed of delivery or packaging of the product.
February 3, 2026
Reply from RadonSeal
We aim to please!
Thank you for taking the time to share your review. We truly appreciate it.
Kind Regards,
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Customer Support
RadonSeal
I had to refuse the delivery "CORRECTION!"
I had to refuse the delivery. You messed up the shipping. 2 packages with same label. I. E. you only paid for one so it came shipping due! Scott.
Please resend correctly.
"CORRECTION " I blamed the wrong company. Their products arrived on time, no problems. Sorry SHP
February 3, 2026
Reply from RadonSeal
Thank you for bringing this to our attention, and we apologize for the inconvenience this has caused. This was due to a human error on our part.
If you haven’t already, please contact us directly so we can resolve the issue promptly.
Kind Regards,
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Customer Support
RadonSeal
Easy Peasy
Super easy to work with and multiple applications to choose from. I started with grinding down to get old and newer concrete to match from stain, sap, and not so great concrete work. Make sure you start out with a completely dry and clean surfaces before applying and preferably not in full sun. I applied 2 coats. The trick is to apply wait for it to absorb and repeat within 5-10 minutes while it still wet. Don’t freak out if it’s patching and blotchy when it dries it will be more uniform. I applied with a hand pump sprayer from Harbor Freight and a roller. It came out perfect! A big shoutout to the customer service they lead me in the right direction and gave me great advice and support. I definitely would recommend and purchase there products again. FYI when reading reviews not all consumers follow directions so please don’t get discouraged about any products for that matter.
January 25, 2026
Reply from RadonSeal
We really appreciate your detailed review of RadonSeal Concrete Sealer. It was a pleasure working with you, and we sincerely value your support of our products!
Kind Regards
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Team RadonSeal
The product says do not freeze but was left on front step all day when below freezing temps.l
The product says do not freeze but I came home to find the box on my porch when the temp was well below freezing. So i guess it's ruined and I'm out $92.
RadonSeal says the product is not hurt by freezing so I guess I was jumping the gun a little. Review updated.
February 1, 2026
Reply from RadonSeal
Hey David,
Thank you for taking the time to leave a review.
The good news is that the product is perfectly fine to use. Had you reached out to us with your questions first, we would have been happy to provide clarification before your review.
Freezing temperatures do not affect the integrity or performance of the product itself. The warning applies only to the packaging and handling, as the containers may crack, warp, or break when the liquid expands during freezing.
If your product arrives partially frozen or slushy, simply allow it to thaw for a couple of days before use.
Kind Regards,
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Customer Support
RadonSeal
Shipping was quick
Shipping was quick, product has not worked so far applied it 2 times
January 28, 2026
Reply from RadonSeal
Hi Hans,
We appreciate your review and support.
Efflorescence can sometimes be stubborn to remove, and chemical cleaners can only do so much before mechanical methods are required to fully remove the deposits.
If you need further assistance, please contact a product representative who can help guide you further.
Cheers,
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Customer Support
RadonSeal
Reply from RadonSeal
We appreciate you taking the time to leave a review and for your support.
Kind Regards,
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Customer Support
RadonSeal
The best sealer ever!
January 26, 2026
Reply from RadonSeal
Thank you for the great feedback! We’re glad to hear you had such a positive experience and truly appreciate you taking the time to share it. Enjoy the results, and thanks for choosing RadonSeal.
Reply from RadonSeal
Thank you for your review! Good to hear the product worked well for fixing your concrete cracks. Much appreciated.
Thorough explanation
The thorough explanation of your products was extremely helpful. Based on that I feel confident that the concrete sealer will do the job I had hoped.
January 22, 2026
Reply from RadonSeal
Thank you for your support! Please contact us if you need further expert assistance.
Why call someone to do it and pay over…
Why call someone to do it and pay over $1000 dollars when you can do it yourself. Just take your time and seal the crack and the plastic pieces so it seals completely so nothing comes out when you start the process. Do not make any sealer get inside the plastic pieces. Don’t panic if nothing is coming out of the next port when squirting the sealer. It will come out after a while. It might take up to 2 minutes because it travels all the way through while squeezing. Great sealer ! Thanks !!
January 20, 2026
Reply from RadonSeal
We appreciate you taking the time to share such a detailed review, highlighting the DIY benefits and offering helpful tips for others using the product. Thanks again for your support!
Awesome Customer Service
Accidentally ordered epoxy instead of urethane. Cheryl caught it and let me know. Great customer service! Great products.
January 20, 2026
Reply from RadonSeal
We’re keeping an eye out for you! Thank you for your continued support, truly appreciated.
I have been calling for two days left…
I have been calling for two days left several messages and an email with no return call.
January 19, 2026
Reply from RadonSeal
Thank you for taking the time to leave your review. We apologize for missing your call initially, as our office was operating on holiday hours at that time. We have since connected with you and appreciate the opportunity to follow up.
Kind Regards,
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Customer Support
RadonSeal
Excellent..
January 18, 2026
Unprompted review
Reply from RadonSeal
Thank you for your business and for taking the time to leave a review. We truly appreciate your support for our products.
Kind Regards,
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Customer Support
RadonSeal
Easy & fast !
January 13, 2026
Reply from RadonSeal
Thank you for your business and for taking the time to leave a review.
Kind Regards,
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Customer Support
RadonSeal
Reply from RadonSeal
Thank you for your business. We ship via Ground Delivery, which typically delivers to the contiguous U.S. within 1–3 business days.
Shipping Details: https://www.radonseal.com/shipping-and-return-policy.htm
Kind Regards,
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Customer Support
RadonSeal
Small town honest customer service.
The customer service over the phone was amazing. The gentleman I talked to walked me through all the products I had questions on for 45min. He did not try to upsale me and even talked me out of one of their products I was going to purchase because it wasn’t the right application for what I’m trying to accomplish. He gave me tips and tricks of other products I can use.
January 6, 2026
Reply from RadonSeal
Thank you for taking the time to share this feedback.
Glad to hear that our team was able to provide thorough, honest guidance and help you select the right solution for your application. We take pride in offering straightforward advice and practical recommendations without pressure.
We truly appreciate your business!
Kind Regards,
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Customer Support
RadonSeal
Excellent service and shipping of the…
Excellent service and shipping of the product. Can’t thank you enough for the quick turnaround in receiving the order. It kept my project moving forward. Thank you!
December 19, 2025
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