Recommended Standards and Practices for Radon Resistant Passive Construction in Slab-on-grade Houses

The State of Florida has developed a draft radon standard for new residential construction. A study was conducted to evaluate the effectiveness of the standard's features in controlling radon entry in new houses built over relatively high radon potential soils. Special attention was given to foundation preparations and slab placements to insure that the draft standard requirements were being met and to identify areas or practices that would assist in achieving (he desired results. The combination of using a nigh range water reducing admixture in the concrete mix, slab reinforcement at re-entrant comers and around large work spaces, and other prescribed activities such as vapor barrier and slab penetration sealing performed well in achieving the objective. Recommendations are made for more specific code language and guidance. Moreover, certain features of local practice will necessitate specific training or retraining in order for adequate implementation of the proposed standards.