Adding continuous insulation to a building increases the effective R-value of the building much more than adding a similar amount of non-continuous insulation (such as in stud cavities). This creates results you can feel, and see. 

Tools & Education

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.

Contains resources on using continuous insulation for compliance with the building codes and energy codes.

Identifies the products supplied by FSC members who have code evaluation reports showing compliance with NFPA 285 testing requirements. 

This report lists foam sheathing products that are available as part of tested assemblies for use as an insulating product in exterior wall assemblies. Available as a sealed code compliance report. 

Research report covering the use of foam sheathing when used as exterior wall sheathing or in exterior walls in Type I, II, III, and IV construction as defined by the IBC. Available as a sealed code compliance report. 

Research report covering the use of foam sheathing when used as exterior wall sheathing or in exterior walls in Type V construction as defined by the IBC. Available as a sealed code compliance report. 

Discusses types of thermal bridges and their impacts as well as repetitive metal penetrations for cladding and component attachments.

Code-compliant details for the use of foam sheathing as thermal insulation in light frame construction. Available as a sealed code compliance report. 

Details and information on the use of CI to avoid thermal bridges

Best Practices

When a builder comes across an R20 + 5ci insulation requirement, it can be easy to think: R20 + 5ci? Why not just use R-25 in the cavity? This guide goes through the math comparing R20 + 5ci and R25 walls.

General installation guidance for foam sheathing used in light frame exterior wall applications

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. 

Covers a “rainscreen” concept with window flanges and furring mounted directly over any thickness of FPIS. Foam sheathing is used as the water resistive barrier. 

Covers a “picture frame” concept with window flanges mounted to the picture frame. Commonly used with foam thicknesses of 3/4 inch to 1-1/2 inches to match common lumber dimensions. Foam sheathing is used as the water resistive barrier. 

Covers a “window buck” concept with window flanges mounted directly over foam sheathing. Most common for wall with more than 1-1/2 to 2-inches of foam sheathing. Foam sheathing is used as the water resistive barrier. 

Guidance for the use of thick foam (>1-1/2") in wood frame buildings 

Practical Research

A comprehensive assessment of the state-of-the-art of water vapor control for modern, code-compliant, light-frame wall assemblies.

Overview of current knowledge supporting the attachment of cladding through foam sheathing used in exterior wall assemblies to comply with the 2015 editions of the International Building Code (IBC) and the International Residential Code (IRC).

This work provides practical guidelines for the mitigation and reduction of thermal bridge problems in existing and new Army facilities. A wide range of building types was investigated from which nine common types were identified, and a number of important thermal bridge details were chosen for each.

This investigation seeks to quantify the effects of thermal bridging in commercial facades and then propose alternative solutions to improve performance by comparing infrared images of recently completed buildings to theoretical models. 

Evaluates data on termite hazard and inspection effectiveness, as well as the presence of hidden pathways in assemblies with and without exterior insulation. Recommends updates to current building code provisions.

Airspace R-values should not be used to displace insulation materials required for energy code compliance unless the air spaces are properly constructed to have no air leakage, or the R-value is appropriately discounted for air-leakage.

Provides data to help better understand the implications and support an equitable, performance-based treatment of thermal bridges for common building assembly conditions and variations.  

Additional Information

A growing number of builders are singing the praises of using rigid-foam insulation between the wall sheathing and the exterior siding, creating a continuous insulating layer.