1.2 Layer of aggregate or sand (4 in.) with geotextile matting installed below slabs AND radon techniques used in EPA Radon Zone 1

To comply with the Indoor airPLUS and Zero Energy Ready Home programs, a layer of aggregate or sand with geotextile matting must be installed below slabs AND radon techniques must be applied in EPA's Radon Zone 1.

The following Solution Center Guides provide more information about these measures:

Guide describing how to install a capillary break under a slab foundation using either polyethylene sheeting or rigid insulation installed over aggregate or over sand and geotextile matting.

Guide describing how to install a radon-mitigating vertical ventilation pipe with various types of house foundations.

Guide describing how to install a radon mitigation fan with various types of house foundations.