WebAll crawlspaces should have a ground covering of polyethylene sheeting that serves as a capillary break and vapor barrier to keep ground moisture and soil gases from entering the crawlspace where they can be pulled into the home through cracks in or around the subfloor. Use ≥ 6-mil polyethylene sheeting. WebVapor retarders have a permeance of 1 perm or less. To put things in perspective, 6-mil polyethylene film has a low permeance (0.05-0.06 perm) when compared to common vapor retarder materials and is actually more of a vapor barrier.
RR-0912: Spray Polyurethane Foam: The Need for Vapor Retarders …
WebApr 15, 2011 · Class I Vapor Retarder: 0.1 perm or less. Class II Vapor Retarder: 1.0 perm or less and greater than 0.1 perm. Class III Vapor Retarder. 10 perm or less and greater than 1.0 perm Test Procedure for … WebMar 1, 2009 · RR-0912: Spray Polyurethane Foam: The Need for Vapor Retarders in Above-Grade Residential Walls John Straube, Rachel Smith, Graham Finch March 01, 2009 Abstract This report is available from the Canadian Urethane Foam Contractors Association. It is reproduced here for convenience. how to pay for trade school
Crawl Space Vapor Barriers- 4 mil, 6 mil, Class 1....Help!
WebJul 27, 2024 · A class 1 vapor retarder is a material that has a perm rating of 0.1 perms or less. Examples of Class 1 Vapor Retarders Materials used for moisture control that are … WebA vapour barrier is required by the National Construction Code (NCC) Volume Two under slab-on-ground construction for all Class 1 buildings and Class 10 buildings where the slab is a continuation of the Class 1 slab. ... As stated above, a vapour barrier is required by the NCC under slab-on-ground construction for all Class 1 buildings and ... WebJun 21, 2024 · These classifications have to do with the permeability, tensile strength and puncture resistance. Class A - Maximum of 0.1 perms, minimum 45 lb/in tensile strength, 2200 grams puncture resistance. Class B - Maximum of 0.1 perms, minimum 30 lb/in tensile strength, 1700 grams puncture resistance. how to pay for traffic school