Systems for homes with a crawl room, no crushed rock under the piece (common in older residences), or an entirely completed cellar, lower level, a garage attic room installation, and so on might cost more. Radon can not be seen, smelled, really felt, or otherwise spotted, other than with an examination. That's why, according to the EPA, the only way to understand for certain if you have a radon issue is to test. This method makes use of suction points that are pierced in the subslab (generally 4 to 6 inch holes that look like hollow pits).