The interior air barrier installation is complete at the Lake Quivira Passive House. We now need to identify any voids that may exist and seal any cracks, seams, or holes. The PDB Crew did a great job of sealing during installation, methodically going through all of the details and junctions of materials changing. However, until we perform a few field testing techniques, there is no way to verify that every penetration is secured.
The video below shows Building Scientist David Hawkins performing multiple testing techniques to isolate and seal penetrations in the interior air barrier.
The process begins by putting the home under a depressurization state using a Blower Door. This depressurization forces outside air into the home through any voids in the air barrier. There are multiple methods to isolate locations of air leakage, some being as simple as using our physical senses of hearing, feeling, and seeing.
Many of the holes are so small, that the air coming through a hole produces a whistle sound. Walking past certain locations in the home, one can physically hear air entering the home. Likewise, by running a hand across certain areas, one can physically feel air blowing through very fine cracks and seams.
After initially addressing the larger penetrations that one can hear or feel, further identification becomes very difficult. At this point, we employ some field tools paired with our sense of sight.
One of the special characteristics of the Lake Quivira Passive House is that it has a crawl space in which we are able to test the floor air barrier. The floor is one of the more difficult surfaces upon which to recognize leaks. The technique we use utilizes a theater fog machine to fill the entire crawl space with smoke. While under a depressurization state, the home sucks the smoke from the crawl space up through any holes in the floor air barrier. Any place where smoke enters the home gets sealed.
Another technique that utilizes field tools and our eyes involves using a lighter around the interior walls. In locations where there may be a leak that can’t be pinpointed, we use a lighter and see how the flame reacts. Any spot where the flame dances in the opposite direction of the wall is immediately secured.
Finally, the most precise tool used to identify air penetrations is an infrared camera. The camera recognizes air temperature differences in a certain location. Anywhere the is a difference in temperature between the air inside the home and the air entering the home shows up on the camera. The infrared camera identified tiny cracks in some existing sealant around a bottom plate, and was then resealed.
The air barrier needs to be as tight as possible, as it is a vital part of our energy efficient home. With all of these techniques and the help of our Blower Door, we were able to isolate and seal remaining cracks, holes, and seams throughout the air barrier, making the Lake Quivira Passive House even tighter.