Blower Door Test Common Air Leaks

Date Published: July 7, 2017

Understanding where to locate and seal blower door test common air leaks is important to ensure that a new construction home will meet the stringent requirements of the IECC and IRC code for maximum air leakage rates. Scott Home Inspection has performed hundreds of blower door tests on new residential homes, remodel-addition projects, and as a component of our energy audit services. We have a solid understanding of where the common leaks occur.

Before you start, it is important to understand what a blower door test is, and when you need a blower door test done on your project. Our blower door testing page will explain the process, and the IECC code requirements. The use of Infra-red scans can help determine the location and severity of leakage occurring.

Blower Door Test Common Air Leaks:

The top areas discovered in a home during blower door testing include:

Rim Joists:

In a conditioned basement or crawlspace, the rim joist area above the foundation wall can be one of the top leak areas. The typical foam gasket seal between the sill plate and the top of the foundation wall typically doesn’t provide enough of a seal to keep cold air from getting into the home.  As heat rises in a home and escapes through upper openings, cold air is pulled into the home from lower leakage areas.  The rim joist all around the perimeter is one of the most common lower level leakage paths we find.

Can Lights:

As the popularity of recessed can lighting continues in homes, these areas represent holes in the ‘thermal barrier’ of a home.  When properly installed, a gasket is used to seal the can light trim kit reducing leakage around the edges of the can.  Efforts to seal can lights to the drywall edge help reduce leakage considerably.

Attic Hatch:

When a hatch or scuttle to access the attic is located within the conditioned space of a home, then the edges of the hatch need to be sealed with weatherstripping and either a weighted, insulated hatch cover installed, or cam locks installed to keep the hatch in place and prevent leakage around the edges of the cover. The weather stripping we see most often is an adhesive style tape. This is one of the most common air leaks we see.