# Best way to vapor-seal existing concrete basement floor **URL:** \ **Category:** Factual Questions\ **Created:** [July 8, 2023, 4:59pm UTC](https://boards.straightdope.com/t/best-way-to-vapor-seal-existing-concrete-basement-floor/986778 "2023-07-08T16:59:08Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![wallewek](https://avatars.discourse-cdn.com/v4/letter/w/71e660/32.png) [@wallewek](https://boards.straightdope.com/u/wallewek)\ **Post date:** [July 8, 2023, 4:59pm UTC](https://boards.straightdope.com/t/best-way-to-vapor-seal-existing-concrete-basement-floor/986778/1 "2023-07-08T16:59:08Z")
Our house has an addition with a concrete basement floor slab. The concrete is of poor quality, and appears to be somewhat porous to air. I want to seal it for proper sub-floor radon removal. It seems to me some sort of penetrating concrete sealant should work. I’ve identified two candidate products: - Quikrete Acrylic Concrete Cure & Seal (liquid in jug) - Xyplex Concrete Waterproofing By Dry Crystallization (powder) Anybody here have experience with both of these for comparison? ---
**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Post date:** [July 8, 2023, 5:12pm UTC](https://boards.straightdope.com/t/best-way-to-vapor-seal-existing-concrete-basement-floor/986778/2 "2023-07-08T17:12:04Z")
I water proofed a badly poured concrete fish pool with, I believe thoroseal. It was masonry based, a powder and mixed with water, not a plastic or paint. I wish that I were certain of the name. ---
**Author:** ![Dereknocue67](https://avatars.discourse-cdn.com/v4/letter/d/6de8d8/32.png) [@Dereknocue67](https://boards.straightdope.com/u/Dereknocue67)\ **Post date:** [July 9, 2023, 7:58am UTC](https://boards.straightdope.com/t/best-way-to-vapor-seal-existing-concrete-basement-floor/986778/3 "2023-07-09T07:58:10Z")
I have no experience with this product but they claim it seals concrete from radon. > **[RadonSeal Deep-Penetrating Concrete Sealers](https://www.radonseal.com/radonseal-mitigation.htm)** > > Radon mitigation and basement sealer made easy! RadonSeal Deep-Penetrating Concrete Sealer seals indoor and outdoor concrete permanently! ---
**Author:** ![wallewek](https://avatars.discourse-cdn.com/v4/letter/w/71e660/32.png) [@wallewek](https://boards.straightdope.com/u/wallewek)\ **Post date:** [July 9, 2023, 7:29pm UTC](https://boards.straightdope.com/t/best-way-to-vapor-seal-existing-concrete-basement-floor/986778/4 "2023-07-09T19:29:06Z")
Pricey! ---
**Author:** ![Tride](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tride/32/13907_2.png) [@Tride](https://boards.straightdope.com/u/Tride)\ **Post date:** [July 9, 2023, 7:51pm UTC](https://boards.straightdope.com/t/best-way-to-vapor-seal-existing-concrete-basement-floor/986778/5 "2023-07-09T19:51:48Z")
Not really. Have you priced paint lately? $50/gallon is pretty in line for sealants/paint. ---
**Author:** ![wallewek](https://avatars.discourse-cdn.com/v4/letter/w/71e660/32.png) [@wallewek](https://boards.straightdope.com/u/wallewek)\ **Post date:** [July 9, 2023, 9:26pm UTC](https://boards.straightdope.com/t/best-way-to-vapor-seal-existing-concrete-basement-floor/986778/6 "2023-07-09T21:26:22Z")
The stuff I mentioned originally is about that. The Canadian source I found wants to sell me 5 gallons for $300. Plus shipping of course. A gallon would be enough, but they don’t sell it that way. ---
**Author:** ![wallewek](https://avatars.discourse-cdn.com/v4/letter/w/71e660/32.png) [@wallewek](https://boards.straightdope.com/u/wallewek)\ **Post date:** [July 10, 2023, 8:53pm UTC](https://boards.straightdope.com/t/best-way-to-vapor-seal-existing-concrete-basement-floor/986778/7 "2023-07-10T20:53:54Z")
I contacted them again, and there is a 1 gal version that costs about $95, plus another $24 for shipping. Still waiting to hear back from Xypex.