Radon itself is an odorless, tasteless, and visually invisible gas, which means you really cannot know if your home is inflicted with radon without getting radon test kits. If you think your home might be at risk, you should purchase some test kits before choosing to take the necessary steps to protect your home. However, you can also take certain steps to protect your home from radon that will also help protect your concrete generally, from cracking, degradation, and the elements.
The best concrete sealers to use to combat radon, specifically, are products like the Sila-Tek 3500 or the Lithi-Tek 4500. Both of these products are water-based silicate penetrating sealers, designed to penetrate past the surface of the concrete. Once within the concrete, they will both react chemically with the minerals already present in the material to block up the network of pores and hairline cracks through which gases like radon can travel. Once these microscopic passages are blocked up, the radon will not be able to seep into your home.
These two sealers also offer the added benefit of strengthening your concrete itself. As part of the chemical reaction, the silicate particles present in both sealers react to form more calcium silicate hydrate, or CSH, which is the material that gives concrete all of its legendary strength and durability. With the application of the Sila-Tek 3500 or the Lithi-Tek 4500, the concrete will not only be stronger, but it will protect your house by sealing out radon once and for all.