Monitoring of Unvented Roofs with Fibrous Insulation, Diffusion Vents, and Interior Vapor Control in a Cold Climate

Technical Report · Tue Sep 01 04:00:00 EDT 2020

DOI:https://doi.org/10.2172/1677422· OSTI ID:1677422

Ueno, Kohta ^[1]; Lstiburek, Joseph W. ^[1]; Burkett, Helen ^[2]

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1. Building Science Corporation, Westford, MA (United States)
2. National Renewable Energy Lab. (NREL), Golden, CO (United States)

Unvented roof assemblies have been accepted in North American building codes since 2007; code-compliant construction calls for a minimum thickness of “air-impermeable insulation” (based on climate zone) to avoid cold-weather condensation and moisture risks. This is typically implemented with polyurethane spray foam insulation; however, negatives of this material include high first cost and possible adverse environmental impacts. Implementing unvented roofs in a moisture-safe manner with air-permeable fibrous fill insulations (e.g., fiberglass or cellulose) could potentially reduce the first cost of unvented roof designs, allowing for more widespread use. Building unvented roofs in a cost-effective, airtight, and moisture-safe manner opens up options for high-performance house designers and builders.

• Research Organization: National Renewable Energy Laboratory (NREL), Golden, CO (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE), Energy Efficiency Office. Building Technologies Office
• Contributing Organization: Dupont Shelter Solutions; North American Insulation Manufacturers Association; Owens Corning; Nu-Wool; Dorken Systems Inc.
• DOE Contract Number: AC36-08GO28308; EE0007570
• OSTI ID: 1677422
• Report Number(s): NREL/TP--5500-77518; DOE/GO--102020-5450; MainId:27454; UUID:4b5913c5-3fb2-4c0b-b347-e3bf2f430d42; MainAdminID:18509
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
42 ENGINEERING
Building America
buildings
cold climate
unvented roofs