Skip to page content
USDA Forest Service

Research & Development Treesearch

Treesearch Home
About Treesearch
Contact Us
Research & Development
Forest Products Lab
International Institute of Tropical Forestry
Pacific Northwest
Pacific Southwest
Rocky Mountain
Southern Research Station
Help - We Participate  Government Made Easy

Global Forest Information Service

US Forest Service
P.O. Box 96090
Washington, D.C.

(202) 205-8333

You are here: Home / Search / Publication Information
Bookmark and Share

Publication Information

View PDF (761.0 KB bytes)

Title: Effects of Exterior Insulation on Moisture Performance of Wood-Frame Walls in the Pacific Northwest: Measurements and Hygrothermal Modeling

Author: Glass, Samuel V.; Yeh, Borjen; Herzog, Benjamin J.;

Date: 2016

Source: 3rd Residential Building Design & Construction Conference - March 2-3, 2016 at Penn State, University Park 2016

Publication Series: Scientific Journal (JRNL)

Description: Continuous exterior insulation on above-grade walls is becoming more common in many parts of North America. It is generally accepted that exterior insulation provides advantages for energy performance, by reducing thermal bridging, and for moisture performance, by warming the wood structural members, thereby reducing the potential for wintertime moisture accumulation. However, the effects of vaportight rigid foam insulation on the drying capability of the wall systems are not fully understood. In this study, temperature and moisture conditions in north-facing and south-facing wall assemblies with vapor-open and vapor-tight exterior insulation were monitored in a natural exposure test facility in the Marine 4 Climate Zone over a two-year period. The wall assemblies included interior gypsum board with latex primer and paint, 2×4 framing with nominal R-13 batt insulation, 11 mm (7/16 in.) oriented strand board, nominal R-5 exterior insulation, and white-color vinyl siding. Exterior insulation was either extruded polystyrene or mineral wool. Measurements and hygrothermal simulations indicated that walls with extruded polystyrene and mineral wool exterior insulation in north and south orientations perform similarly. Moisture content in wood framing and oriented strand board were within safe levels.

Keywords: exterior insulation, continuous insulation, energy performance, building envelope, building enclosure, hygrothermal modeling, Pacific Northwest, wood-frame walls, drying capability, wall systems, temperature, moisture, insulation

Publication Notes:

  • We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
  • This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.



Glass, Samuel V.; Yeh, Borjen; Herzog, Benjamin J. 2016. Effects of exterior insulation on moisture performance of wood-frame walls in the Pacific Northwest: Measurements and hygrothermal modeling. 3rd Residential Building Design and Construction Conference, 2-3 March 2016. Penn State, University Park 2016.


 [ Get Acrobat ]  Get the latest version of the Adobe Acrobat reader or Acrobat Reader for Windows with Search and Accessibility

USDA logo which links to the department's national site. Forest Service logo which links to the agency's national site.