Demonstration of radon resistant construction techniques. Phase 2. Final report. Report for November 1991-February 1993

The report gives results of a demonstration of radon resistant construction techniques. Sub-slab mitigation systems were installed (in accordance with draft standards) in 15 new Florida houses in 1992, and these houses have undergone extensive testing to validate techniques used to prevent radon intrusion. Soil radon levels ranged from just under 500 to over 8000 PCi/l. All systems have been determined to extend negative pressure to practically all areas under the slab. Slabs tended to crack less than expected. Intact vapor barries under new houses prevent radon intrusion through slab cracks in most instances.