multistory buildings that include any residential occupancy;
mixed-occupancy buildings that include any residential occupancy; and
a basement concrete slab in contact with the earth;
a crawl space within the building's conditioned space that has a concrete or earth floor;
a wood foundation floor constructed on or directly above the earth;
slab on grade construction designs;
attached or tuck-under garages, unless the floor, wall, and ceiling assemblies separating the garage from the dwellings are sealed; and
any building configuration that allows radon gas to enter the residential dwelling.
1. Crawl spaces outside the conditioned space of the residential dwelling, when the crawl space is ventilated directly to the outside atmosphere according to IRC sections R408.1 and R408.2; IBC sections 1203.3 and 1203.3.1; Code of Federal Regulations, section 3285.505; and Minnesota Rules, chapter 1350.
2. Hotels and motels.
3. Additions to existing dwellings that do not currently have a radon control system incorporated into the existing dwelling.
When the nonresidential occupancy is in contact with the earth, all assemblies that separate the occupancies must be sealed to prevent the movement of air and airborne gases between the nonresidential and residential occupancies. When the residential occupancy is in contact with the earth and adjacent to a nonresidential occupancy, the residential occupancy shall incorporate a radon control system and all assemblies that separate the nonresidential and residential occupancy shall be sealed to prevent the movement of air or airborne gases.
39 SR 232
February 16, 2015