Code Issues

Restrictive or non-existent codes prohibit the widespread use of some of the components of the Durable Building Envelope Tech Set. These codes are discussed below. Installation codes pertaining to relevant building components are also listed.

Foundations

The International Residential Code (IRC) contains provisions for many types of foundations in various soils, including reinforced poured concrete (ACI 318), wood (AF&PA 16), and "approved" precast foundations. Precast foundation panels require case-by-case local approvals.

The IRC requires foundation drains around all concrete or masonry foundations, except those in Type I soils.

The IRC requires a bituminous emulsion (dampproof) coating (or similar) on the exterior of concrete foundations or 2-ply hot mopped felt, 6 mil poly, or 55 pound roll roofing coverage of foundation walls in areas with high water tables. Bituminous emulsions have generally met ASTM D 2939 standards for emulsified bitumens used as protective coatings, but the code doesn't specifically address this standard for performance. Foundation moisture barriers that are applied in sheets, like polyethylene, foundation drainage panels, and other proprietary products, will often be tested to meet ASTM standards for tensile strength (D 412), permeance (E-96-B), puncture resistance (E-154), and water absorption (D-570), again, not specified in the code.

The IRC prescribes foundation plate anchorage schedules and fine grade slope adjacent to foundation.

Framing

The IRC prescribes 2x4 wood stud framing at 24" o.c. for walls of structures supporting either one floor or a ceiling and roof. Wood 2x6 framing at 24" o.c. will support one floor, a ceiling, and a roof. A single top plate can be used on structural walls if corners and headers are secured with steel plates. In-line framing (+5") is required for all 24" o.c. structural walls unless three top plates are installed.

The IRC has a provision for wood structural box headers that can be insulated.

The IRC prescribes steel 2x4 (350S162) for one- and two-story construction with a ceiling and roof, dependent on gauge. All steel must be framed in line. Steel L Headers are permitted by the code by its reference to AISI Standard for Cold-formed Steel Framing-Header Design (COFS/Header Design).

Structural insulated panels are not yet referenced in the code. The manufacturer should file an ICC-ES (or equal) report detailing the panel's structural capability, surface burning characteristics, and fire resistance. Regional code approval/pre-construction consultation with the building official is suggested. Details on assembly, connections, and creating openings and raceway cutouts will vary by manufacturer.

Manufactured Components

Pre-manufactured components, such as trusses and insulated headers, should have a nationally recognized approval rating (like a TPI stamp or ICC-ES report) and regional code approval/pre-construction consultation with the building official. All of the composite lumbers fall under this alternate materials approach to obtaining approval of products for construction prior to use.

Content updated on 12/7/2005