Testing Building Envelopes for Residential Construction

Whether or not to test a new-home building envelope is a question many builders are asking themselves, as well as third-party inspection agencies and local and state code officials. 

Here are a few things builders need to take into account to help answer the question:

o   States have adopted the requirements for building envelope testing from different versions of the International Energy Conservation Code (IECC). The U.S. Department of Energy provides the status of state energy code adoption on its Building Energy Codes Program website. 

o   The builder needs to determine which version of IECC applies to his residential construction. The builder needs to confirm with the local code official what’s required to secure the certificate of occupancy. A certificate of occupancy is a document issued by a local government agency or building department certifying a building’s compliance with applicable building codes and other laws, and indicating that it’s in a condition suitable for occupancy. The procedure and requirements for the certificate vary widely from jurisdiction to jurisdiction and based on what type of structure it is.

o   Where local code officials enforce the IECC 2009, an alternative to building envelope testing may be allowed. This allowance is referred to as the visual inspection option, and it states: “Building envelope tightness and insulation installation shall be considered acceptable when the items listed in Table 402.4.2, applicable to the method of construction, are field verified. Where required by the code official, an approved party, independent from the installer of the insulation, shall inspect the air barrier and insulation.” 

o   Where local code officials enforce the IECC 2012, the visual inspection option is no longer allowed and the only means of compliance to the 2012 IECC is testing the home’s building envelope.

Testing the home building envelope is a simple process that requires the home to be depressurized by a blower door test assembly. The test results tell you how many air changes per hour (ACH) the home allows based on the tightness of the building envelope. The lower the ACH, the tighter the building envelope and the better the techniques used by the builder for constructing the foundation, walls, doors, windows and roof.

For additional information about building envelope construction and testing, contact us at 1.574.773.7975 or ntainc.com.