How does radon get into a building?
Most indoor radon comes into the building from the soil or rock beneath it. Radon and other gases rise through the soil and get trapped under the building. The trapped gases build up pressure. Air pressure inside homes is usually lower than the pressure in the soil. Therefore, the higher pressure under the building forces gases though floors and walls and into the building. Most of the gas moves through cracks and other openings. Once inside, the radon can become trapped and concentrated. Openings which commonly allow easy flow of the gases in include the following: • Cracks in floors and walls • Gaps in suspended floors • Openings around sump pumps and drains • Cavities in walls • Joints in construction materials • Gaps around utility penetrations (pipes and wires) • Crawl spaces that open directly into the building Radon may also be dissolved in water, particularly well water. After coming from a faucet, about one ten thousandth of the radon in water is typically released into the ai
