Passing Your Blower Door Test

Michigan updated the code book a few years ago, one of the biggest changes is that all new homes and remodels where square footage is added must pass a blower door test. If you haven’t built a home in a few years this rule may have caught you by surprise. If you are wondering what a blower door test is I suggest you click here. If you know the basics here are some tips and pointers on how to pass your blower door test:

1- Have an airsealing plan BEFORE you start construction. Here are a few common strategies:

  • Exterior rigid foam on all exterior walls taped an sealed at all seams and to bottom plate.

  • Using acoustical caulk or foam to seal all studs from the inside to the sheeting (commonly called picture framing)

  • Spraying all exterior cavities with hard foam (this is one of the more expensive methods but can be effective especially if you do not know what you are doing)

  • Sealing with Aerobarrier once drywall is up (cheaper than sprayfoam and can give you a very tight envelope!)

  • There are many other ways to create a tight envelope as wall as many combinations. For more options or more details feel free to check out Green Building Advisor

2- Make sure your sub-contractors are on board with the airsealing plan and are willing to seal all their penetrations. Make sure the sight supervisor or builder is keeping trades accountable!

3- Make sure all major penetrations are properly sealed.

  • Foam or gasket around windows and doors when installing.

  • Foam or caulk around all plumbing, electrical and HVAC penetrations to the exterior.

  • Make sure attic access is insulated and gasketed.

  • Make sure all chimney chases are sealed off to attic.

  • Seal around bath fan penetrations and make sure bathfans have operable dampers.

4- Make sure you use Sill-Seal or caulk when installing exterior walls.

5- Rim Joists are on of the main areas where leakage happens. I recommend using hard spray foam or cutting and caulking rigid foam board into these areas (fiberglass is not an air sealant!)

6- Details matter! Make sure all the little things are taken care of before the test!

  • Please have all windows closed and locked the day of the testing.

  • Make sure all trim around windows is caulked.

  • All plumbing fixtures should have water in the trap.

  • Make sure all fireplace dampers are closed.

  • If dryer is not installed please seal off dryer vent with tape.