For the airtightness test, the building’s airtight envelope (floor joists, walls, attic floor) must be complete, the doors and windows installed, and all penetrations finished and sealed (ventilation ducts, range hood, flue ducts for fireplaces and sauna stoves, water and sewer lines, central vacuum cleaner exhaust pipes, pipe penetrations in the floor joists, e.g., cable protection conduits for electricity or geothermal heating).
The measurement can be performed even if the house does not yet have a door or if one of the doors is a temporary door used during construction. In this case, the doorway may be no more than one meter wide and must be equipped with jambs or a frame into which the measurement door can be installed.
If there is a garage attached to the house, the garage door must be installed.
It is advisable to leave the air/vapor barrier visible so that any leaks that are discovered can still be repaired. However, this is not necessary.
The ventilation unit does not need to be installed. It is easier to take the measurement before the ventilation unit is installed.
The following installations must be completed before the measurement:
Exterior doors and windows
- Around windows and doors, the joint between the frame and the exterior wall has been sealed with urethane, tape, a wood strip, or a suitable sealant.
- The door thresholds have been sealed.
Floor joists
- The pipe penetrations have been sealed with urethane or a suitable sealant against the floor.
- The joint between the subfloor and the wall has been sealed. (A tried-and-true, though not mandatory, method is to cut the underlayment on top of the concrete and then apply a suitable sealant to the joint between the wall and the subfloor.)
Attic floor
- The joints in the attic floor’s vapor barrier (vapor barrier board, vapor barrier film, or urethane panels) have been sealed throughout and connected airtight to the exterior wall’s vapor barrier.
- The joists for the attic floor have been installed. The measurement is performed under negative pressure, which can damage the attic floor’s air barrier if the joists are missing.
- The pipe penetrations have been sealed with collars and vapor barrier tape against the air barrier of the attic floor.
- The stove's flue has been sealed off from the air barrier in the attic floor.
Walls
- The air barriers on the walls have been sealed throughout.
- The openings in the exterior wall (the fresh air duct of the ventilation unit, the exhaust pipe of the central vacuum cleaner, cable conduits, etc.) have been sealed with urethane or a suitable sealant.
- The airtightness test should be performed before painting and plastering work, or a few days after such work has been completed.
You give
- The concrete block walls and the chimney have been plastered throughout on the inside (including the basement walls and the walls in the utility room). Unplastered walls allow air to pass through, which affects the accuracy of the measurements.
- Ensure that the air barrier in laundry rooms, saunas, and utility rooms is continuous. The vapor barrier must be fully installed and tightly connected to the air barrier in the building envelope.
- Temporary openings created during construction and any other gaps in the building envelope must be sealed.
- The building has electricity.
- In a duplex, the openings between the units must be sealed.
- In buildings with two or more floors: There must be a staircase between the floors, as the person conducting the measurement must be able to move between the floors inside the building.
- The roof safety products must be installed, as the person performing the measurement may need to seal the chimney flue or ventilation ducts on the roof.
Before the measurement:
- Close the windows and doors securely.
- Do not light a fire in the fireplace for about 24 hours before the measurement, as the person performing the measurement will seal the flue either with tape or a rubber sealing balloon.
- If the house is unheated, turn on the heater about 24 hours before the measurement. The goal is to create a temperature difference between the outside and inside of the house so that leaks can be located using a thermal camera.
- To locate a leak, building materials, furniture, and other movable objects that can be moved without undue difficulty should be moved so that they are no closer than approximately one meter from the exterior walls of the house.
- Make sure there is sufficient general lighting in the building so that the measurement can be taken without any problems.
During the measurement:
- Set aside 3–4 hours for the measurement. For most of that time, you can work on other tasks at the same time.
- It’s good to have a carpenter on site who can make the necessary repairs.