Taped foam sheathing can be used as an effective and durable water resisitive barrier, meeting code requirements without the extra cost or labor associated with using a separate WRB product, solving the stucco moisture problem with CI. 

Tools & Education

This wall calculator is a tool to help coordinate energy code thermal insulation compliance and building code water vapor control compliance for a proposed wood frame wall assembly on a commercial or residential building.

Covers the use of foam sheathing as an integrated water resistive barrier. Available as a sealed code compliance report. 

This session, presented at IBS 2017, provides actionable prescriptive guidelines for integrated insulation and vapor control strategies.

Summary of WRB water penetration testing requirements and recommendations for the fair treatment of WRB products based on one performance-based benchmark for water-penetration resistance of WRB assemblies. 

Best Practices

Step by step instructions on how to install foam sheathing as a WRB system

This presentation addresses two practices with proven ability to improve water penetration resistance of fenestration product installation: Sill pans and flashing for rough opening drainage, and air-sealing of the interior side of the rough opening gap.

Covers the most common method of flanged window installation over foam sheathing where the flanges are mounted directly over up to 2" of foam sheathing. Foam sheathing is used as the water resistive barrier.

This guide from Building America addresses various means of applying foam sheathing on 2x4 wood framed walls in climate zones 3-5, including integration with other components (e.g., windows and cladding) for foam thicknesses up to 1-1/2”. It also addresses air barriers,  water vapor retarders, and use of foam sheathing as a WRB or in combination with a separate membrane WRB.

Practical Research

This Research Report provides actionable guidelines to effectively consider, evaluate, and manage the balance of wetting and drying potential in common above-grade, light-frame wall assemblies in a broad range of climate conditions. 

Summarizes requirements found in the various standards and evaluation agency criteria, evaluates relevant and available test data, and provides a recommendation for the fair treatment of all products based on one performance-based benchmark for water-penetration resistance of WRB assemblies.

Additional Information

This guide provides information and recommendations to the following groups: insulation contractors; general contractors; builders; home remodelers; mechanical contractors; and homeowners.

The water control layer of the wall has to connect to the water control layer of the window.

Four tests can help to sort out the dilemma of whether a water control layer can have holes and function as intended. 

One of the dirty little secrets that never gets talked about is that water leaks through building papers, building wraps and housewraps and runs down between them and the sheathings that they cover.

Summary of research done to examine WRB building code provisions and test methods and to perform independent laboratory testing to study WRB performance