One of the (several) crucial components of building a Passive House is the air sealing. In order to obtain certification a level of 0.6 Air Changes per Hour (ACH) must be met. To put that into perspective a drafty old farmhouse may have an ACH of 10+. This means that the entire volume of air may be replenished in the home 10 or more times per hour when it is pressurized (or depressurized) to 50 pascals. A typical new build home may be between 3 and 6 ACH. An R2000 home needs to meet 1.6 ACH. Meeting the 0.6 ACH requires careful planning of penetrations into the home and meticulous air sealing with tapes designed for the job.
We have chosen to use a layer of OSB sealed with SIGA tape as our air sealing layer in the home. SIGA tapes are known internationally for use in air sealing and they have different tapes for different purposes. Interior air sealing is best completed with SIGA Rissan. This tape is to cover all the joints between the OSB as well as the joint between the OSB and the concrete. The OSB will run the entire height of the load bearing wall as well as on the ceiling of the second story. Any penetration into the home such as the supply and exhaust for the HRV system as well as the windows and doors must be carefully sealed to prevent any air from entering or escaping the home.
When the air sealing is complete we will have our first blower door test completed. We are excited that students from Holland College will be coming to perform this test. We will be ready this week for the blower door test to be conducted. I must admit, I’m nervous about it! I know that we have done everything to ensure that the house will be airtight but it is still nerve racking. I guess it’s like my high school math students; some of them know that they understand the content but they still get test anxiety!
Although I’ve posted some of the pics of the air sealing before I hope that this explanation has helped with understanding it a bit more.