Basic vapor retarder installation

This video details methods for installing vapor retarders using 6 mil polyethylene sheeting (“6 mil poly.”) It also covers best practices for sealing vapor retarders at commonly encountered junctures. In Alaska, 6 mil poly has been the industry standard material for vapor retarders and air barriers in wood-frame construction for close to 60 years. Using current methods, properly installed polyethylene sheeting can reduce air leakage rates to less than 1 ACH50, a rate that generally meets or exceeds North American standards for high-performance homes. It should also be noted that the use of 6 mil poly is required by municipal residential building codes in all of Alaska’s climate zones, from Juneau in climate zone 6 to Fairbanks in climate zone 8. Given 6 mil poly’s integral role in building durability and comfort, it is essential to get the details right. Unfortunately, information on how to install and seal polyethylene vapor retarders is scattered throughout a patchwork quilt of literature, building codes, and building-affiliated professions; methods are often passed on from job to job and person to person. They are thus often particularly inaccessible to builders who are new to the state or to the trade. This video seeks to help remedy that deficiency. It focuses on a set of fundamentals that apply to virtually all 6 mil poly installations, and particularly demonstrates techniques for installations performed by a person working alone. The methods presented here are based on years of experience installing poly solo in a wide variety of conditions. They are by no means the only way to install polyethylene sheeting and we expect and encourage viewers to adapt and improve upon these methods to suit their own needs. The single most important lesson to be learned from this video (demonstrated at 16:14) is that vapor retarder sealant must be run in areas with solid backing in order to establish a clamped connection between the backing and subsequent layers of rigid insulation or drywall. A properly backed, sealed, and clamped polyethylene sheeting connection can be expected to maintain its integrity for the life of the home. For more information on 6 mil poly installation in cold climates, you may want to consult these videos: “Replacing a Ceiling Vapor Retarder” highlights repair of a problematic vapor retarder installation:    • Replacing a Ceiling Vapor Retarder   “Cold Climate Building Techniques and Concepts: Vapor retarder” focuses on installing a vapor retarder on a cathedral ceiling and air sealing around a ridge beam as well as providing targeted detailing information for windows and wall penetrations:    • Cold Climate Building Techniques and Conce...   “Cold Climate Building Techniques & Concepts: Furring in an outside wall” covers furring in a wall and thereby protecting the vapor retarder and gaining additional R-value:    • Cold Climate Building Techniques & Concept...   “Penetrating exterior walls” specifically addresses how to get better air sealing at the vapor retarder for exterior wall penetrations:    • Penetrating Exterior Walls   We welcome questions and discussion in the comments and you can also reach us at [email protected]. CCHRC website: www.cchrc.org CCHRC YouTube channel: @coldclimatehousing Videography and editing by Tom Moran, CCHRC Music: "Motivational inspiring music" by Alexander Blu from https://orangefreesounds.com/. The song is permitted for non-commercial use under license “Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)”