When it comes to walls, the use of continuous insulation can greatly improve performance and simplify design and installation. In particular, foam plastic insulating sheathing (FPIS) products can serve as an air barrier, water resistive barrier, and water vapor control, as well as cut down on the detrimental effects of thermal bridging.

Tools & Education

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


How to apply the IRC bracing provisions for code-compliant dwellings and how the IRC bracing provisions can be used to create maximum value in a diverse housing market.


Code-compliant details for the use of foam sheathing as thermal insulation in light frame construction. 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. 


This DrJ Research Report provided the basis for the current Quick Guide on Cladding Connections to Wood Frame Walls, published in November 2021.


This DrJ Research Report provided the basis for the current Quick Guide on Code-Compliant Vinyl Siding Applications over FPIS ci, published in December 2021. 

Best Practices

In an article for Vinyl Siding Institute, Jay Crandell, P.E. highlights some key resources to help with code compliance when considering combined applications of vinyl siding (including insulated vinyl siding) and foam plastic insulating sheathing (FPIS) products on wood frame walls.

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


ANSI/ABTG FS200.1 – 2022 contains a wealth of practical and actionable guidance for code-compliant use of foam sheathing on above-grade walls. This comprehensive resource is aimed at meeting the needs of designers, builders, installers, manufacturers, and code officials. Learn more here or download a copy. 

ANSI/ABTG FS 100-2012 (R2018) establishes wind pressure resistance requirements for foam plastic insulating sheathing (FPIS) products used as exterior wall sheathing,

In August 2004, the ASHRAE Journal ran Joseph Lstiburek's paper enttitled “Understanding Vapor Barriers.”  After almost two decades, he has updated it to focus on rain and air control as well as vapor control – all things that “walls” need to do – hence the revised title, “Understanding Walls.”

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

Installation guidance for cladding installation through foam sheathing used in light frame exterior wall applications

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.

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.

Additional Information

In the Aug/Sept 2022 issue of Fine Homebuilding, Fernando Pagés Ruiz discusses how he omitted the OSB on this spec home to save money, while still making sure his build had reliable structural quality.

Research findings on the long-term performance of cladding attachments through foam sheathing. Covers fastening techniques, material expansion and contraction, and deflection (creep).