The readings below are related to Jonathan Smegal’s May 2017 LAB Event on vented and unvented design options for attics and cathedral ceilings. Together, these resources provide a general introduction to this topic and related research.
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Top 5 Things to Read:
#1: Re-thinking Ventilated Attics: How to Stop Mold Growth in Coastal Climates
Marcus Dell, RDH, available at rdh.com.
Discusses mold growth on the underside of sheathing in the Pacific Northwest, outlining causes and possible solutions. See also Why Wood Frame Attics Get Wet & Moldy in the Pacific Northwest, by Graham Finch, Robert Lepage, Lorne Ricketts, James Higgins, and Marcus Dell, RDH.
#2 BSD-149: Unvented Roof Assemblies for All Climates
Chris Schumacher, RDH, available from buildingscience.com
This buildingscience.com article provides an overview of how unvented closed-cell SPF designs work.
#3: How to Build an Insulated Cathedral Ceiling
Martin Holladay, available from greenbuildingadvisor.com
Answers some commonly asked questions on cathedral ceilings from GBA’s readers.
#4: Canadian Spray Foam Guide
Jonathan Smegal, John Straube, and Aaron Grin, RDH, available from cufca.ca
Recommended enclosure details using light-density (0.5 pcf) and medium-density (2.0 pcf) polyurethane spray foam.
#5: Issues Related to Venting of Attics and Cathedral Ceilings
Anton TenWolde and William B Rose, available from www.fpl.fs.fed.us
This 1999 article is outdated as far as codes, but useful for its building science.