Building Envelope Code Changes and Builders

Building Envelope

Because international building codes are regularly updated, it is always important to look at the recent changes to the International Residential Code and what it means to builders. Not surprisingly, the 2012 update of the International Residential Code (IRC) includes more demanding energy performance standards than the 2009 update. Also, it simply references many of the requirements set forth in the International Energy Conservation Code (IECC) so that there is no longer any difference for a builder in following one over the other.

Some of the most important changes include the need for a tighter building envelope, the use of energy-efficient LED lighting, and the installation of more energy-efficient windows. Insulation requirements increase, especially in colder climates where any exterior wall insulating approach must now address thermal bridging through studs. In most instances, this means the use of exterior insulation.

Until the 2012 update, builders could choose to focus on compliance with either the IRC (Chapter 11) or the residential portion of the IECC. Because the 2009 IRC code varied from the IECC code to a degree, some builders gravitated toward the easier-to-follow IRC standards. Now, there is essentially no difference between the two.

Continuous Barrier Required in Building Envelope

Key provisions are found in IECC Table 402.4.1.1, entitled “Air Barrier and Insulation Installation,” provides an air-sealing checklist written in clear, mandatory language. Some 2009 code updates that lacked clarity are now unambiguous.

The table in the 2012 IECC requires that “a continuous air barrier be installed in the building envelope. Breaks or joints in the air barrier shall be sealed.” The update prohibits the use of air-permeable insulation alone as a barrier.

Also, previous codes made it possible for a builder to select one of two possible compliance methods. A compliant builder was to either follow the IECC checklist or conduct a blower-door test. The updated 2012 code now requires both.

The blower-door test establishes the air leakage rate, which is more strict in climate zones three through eight than in climate zones one and two. Section 402.4.1.2 of the 2012 IECC states that the air leakage rate shall not exceed three air changes per hour zones 3-8, and it shall not exceed five air changes per hour in zones 1-2.

Green Builders Gain Advantage

A report in Green Building Advisor suggests that “The 2012 IECC is a significant improvement over all previous US energy codes.” However, it cautions that full enforcement would require additional training for many thousands of local officials and increased budgets for numerous local building departments. As a result, builders will find that the 2012 IECC update is enforced in some jurisdictions and not in others.

However, where compliance is not required, there is still a distinct advantage in following the updated code. A builder following the more stringent performance requirements demonstrates to prospective clients that there’s a desire to pursue progressive green building standards in the industry. Compliant builders have the opportunity to point out how meeting the requirements of the most recent code update results in energy savings and reduced emissions.

A Compliant Air/Moisture Barrier

DELTA®-VENT SA is a moisture-resistive air barrier that includes the characteristics necessary to comply with the more stringent requirements of the 2012 code update. It is a three-ply membrane featuring a middle vapor-permeable layer sandwiched between two outer layers of the spun polypropylene.

DELTA®-VENT SA is a WRB that minimizes air migration, provides a watertight building envelope and allows for moisture and humidity to escape wall cavities. This addresses the problem of condensation inside wall cavities that potentially leads to mold, mildew and other problems.

Dörken delivers innovative, high-performance air and moisture barriers for commercial and residential construction sold under the DELTA® brand name. A North American manufacturer based out of Beamsville, Ontario, Dörken Products, Inc. is a subsidiary of Ewald Dörken AG, a leading European developer and manufacturer of waterproofing and drainage products sold worldwide. Dörken is known for delivering premium products while providing educational programs and full technical support. For more information, call 1-888-4DELTA4 (433-5824) or visit