heet over the first sheet to cover any rips in the first sheet (make sure the first sheet is dry and free of organic matter). Seal the top sheet to the walls.
b. Lay a vinyl runner or extra plastic over any areas that will get traffic, such as a service path to the furnace.
c. Cover the single sealed layer of polyethylene with a concrete slab 2 or more inches thick. (See the guide Capillary Break at Crawlspace Floor – Polyethylene Sheeting under Concrete Slab.)
Visually inspect the crawlspace to ensure that the earthen floor is completely covered with a layer of polyethylene sheeting at least 6 millimeters thick, that the sheeting extends up the sides of each wall or pier and is mechanically fastened with wood furring strips or other fasteners, and that any seams in the plastic are overlapped 6 to 12 inches and taped or sealed.
ENERGY STAR Version 3 (Rev 08) Water Management Checklist, 1. Water-Managed Site and Foundation. 1.4. Capillary break at all crawlspace floors using ≥6 mil polyethylene sheeting.
Polyethylene sheeting is not required in Dry (B) climates shown in the International Energy Conservation Code (IECC) climate map (2009 IECC, Figure 301.1and Table 301.1), except in U.S. EPA Zone 1 Radon areas (see the EPA Radon Map). Polyethylene sheeting is also not required for raised pier foundations with no walls. Click here for the 2009 IECC Interactive Climate Zone Map.
Although not required in dry climates designated as EPA Radon Zone 2 or 3, polyethylene sheeting is still recommended, as is a passive radon venting system, to help keep soil gasses out of the home and to mitigate radon should it be present at the house site.
International Energy Conservation Code (IECC) Climate Regions
ENERGY STAR Certified Homes (Version 3/3.1, Revision 08), Water Management System Builder Requirements
1. Water-Managed Site and Foundation:
1.4.2 Capillary break at all crawlspace floors using ≥ 6 mil polyethylene sheeting, lapped 6-12 in., & lapped up each wall or pier and fastened with furring strips or equivalent AND 1.4.3 Secured in the ground at the perimeter using stakes 3, 4, 5
(3) Not required in Dry (B) climates as shown in 2009 IECC Figure 301.1 and Table 301.1.
(4) Not required for raised pier foundations with no walls. To earn the ENERGY STAR, EPA recommends, but does not require, that radonresistant features be included in homes built in EPA Radon Zones 1, 2 & 3. For more information, see www.epa.gov/indoorairplus.
(5) For an existing slab (e.g., in a home undergoing a gut rehabilitation), in lieu of a capillary break beneath the slab, a continuous and sealed Class I or Class II Vapor Retarder (per Footnote 7) is permitted to be installed on top of the entire slab. In such cases, up to 10% of the slab surface is permitted to be exempted from this requirement (e.g., for sill plates). In addition, for existing slabs in occupiable space, the Vapor Retarder shall be, or shall be protected by, a durable floor surface. If Class I Vapor Retarders are installed, they shall not be installed on the interior side of air permeable insulation or materials prone to moisture damage.
(7) The 2009 IRC defines Class I vapor retarders as a material or assembly with a rating of ≤ 0.1 perm, using the desiccant method with Proc. A of ASTM E 96. The following materials are typically ≤ 0.1 perm and shall not be used on the interior side of air permeable insulation in above-grade exterior walls in warm-humid climates or below-grade exterior walls in any climate: rubber membranes, polyethylene film, glass, aluminum foil, sheet metal, and foil-faced insulating/non-insulating sheathings. These materials can be used on the interior side of walls if air-permeable insulation is not present (e.g., foil-faced rigid foam board adjacent to a below-grade concrete foundation wall is permitted).
Note that this list is not comprehensive and other materials with a perm rating ≤ 0.1 also shall not be used. Also, if manufacturer’s specifications for a product indicate a perm rating ≥ 0.1, then it may be used, even if it is in this list. Also note that open-cell 