WebViper II products are multi-layer (co-extruded), virgin polyolefin under-slab vapor barriers/retarders. The virgin resin used to manufacture Viper II contributes to its long-term stability and prevents the material from … WebClass II vapor retarders (greater than 0.1 perms and less than or equal to 1.0 perms): Unfaced expanded or extruded polystyrene 30 pound asphalt coated paper Plywood Bitumen coated kraft paper Class III vapor retarders (greater than 1.0 perms and less …
What is a Class A Vapor Barrier Material? - Americover
WebDec 9, 2024 · A Class II vapor barrier typically has a permeability greater than 0.01 perms. This class is semi-permeable, meaning it is not entirely impermeable to water vapor. These include the following materials; Bitumen coated Kraft paper Thirty-pound asphalt coated paper Unfaced expanded polystyrene Class III WebThe ICC building codes require a Class I or II vapor retarder on the inside of insulated assemblies (IRC 1405.3 and IBC R702.7) in Climate Zones 5, 6, 7, 8 and Marine 4. This is to prevent warm and more humid interior air from moving through the insulation and condensing on the cold "condensing surface" during outward vapor drive in winter. mcps pay scale
Moisture Control Vapor Retarders, Residential, Installing
WebThese barriers are required where there is cladding on the house that doesn't allow enough drying to the outside. Type 2 vapor barriers, the basic vapor barrier for ordinary conditions, are defined as having a … WebClass I vapor retarder has a 0.1 perm or less. Class II vapor retarder has a perm of 0.1 to 1.0. Class III vapor retarder has a perm of 1.0 to 10. Any vapor barrier or retarder sheet with a rating above 10 perms is referred … WebJul 21, 2024 · IRC Class I, II, and III Vapor Barriers Vapor barriers are defined as either Class I, II, or III by the International Residential Code (IRC) based on how permeable … mcps partnerships