For the tightness measurement, the building’s airtight envelope (base floor, walls, roof) must be complete, the doors and windows must be installed and all lead-throughs must be complete and sealed (ventilation ducts, extractor hood, fireplace and sauna stove flues, water pipes and sewers, central vacuum system’s discharge pipe, base floor lead-through pipes, such as shield pipes for power supply or geothermal heat pipes, etc.).
The measurement can be conducted even if one door is still uninstalled or has door used for the construction phase. In this case, the door opening must be less than 1 metre wide and have jambs or a frame to which the framework for the measurement door can be installed.
The air/vapour barrier should still be visible so that any possible leaks can be easily repaired. This is not necessary, however.
The ventilation unit does not need to be installed. It is easier to conduct the measurement when the ventilation unit has not yet been installed.
The following installations must be complete before the measurement:
External doors and windows
- The joint between the window and door jambs and the external wall has been sealed with urethane / tape / sealing strip / suitable sealing compound.
- Door sills have been sealed.
Base floor
- Pipe lead-throughs have been sealed with urethane/suitable sealing compound to the floor.
- The joint between the base floor and wall has been sealed. (An effective but not mandatory practice is to cut a foundation strip in the surface of the casting and then apply suitable sealing compound on the joint between the wall and base floor.)
Roof
- The seams of the roof air barrier (air barrier paper, vapour barrier plastic or urethane plates) have been sealed thoroughly and connected to the external wall’s barrier in an airtight manner.
- The supports for the roof structure have been installed. The measurement will be conducted at boosted negative pressure, which may damage an unsupported roof air barrier.
- The pipe lead-throughs have been sealed with collars and vapour barrier tape to the roof air barrier. The fireplace flue has been sealed to the roof air barrier.
Walls
- The air barrier of the walls has been sealed throughout.
- Lead-throughs that go through the exterior wall (ventilation unit’s fresh air duct, central vacuum system’s discharge pipe, electrical pipes, etc.) have been sealed with urethane/suitable sealing compound.
- It is a good idea to conduct the tightness measurement before painting and filling work or a few days thereafter.
Other things to note
- The block walls and chimney have been fully faced from the inside (including basement and technical room walls). A block wall/flue that has not been faced will leak air that will deteriorate the measurement result.
- It has been ensured that the envelope air barrier is uniform at the position of wet rooms, saunas or technical rooms. The water insulation must be complete and connected to the envelope’s air barrier in a tight manner.
- Temporary lead-throughs for the construction phase and any other holes in the envelope have been sealed.
- Regular mains power is available in the building.
- In the case of semi-detached houses, the lead-throughs between the housing units must also be sealed.
- Buildings with two or more floors: Ladders must be provided between the floors so that the person conducting the measurements can access all floors from inside the building.
- Roof safety equipment must be in place as the person conducting the measurement may need to seal the fireplace flue or some ventilation ducts from the roof.
- If a garage is connected to the building and the same ventilation system, the external door must be installed. If the garage has its own ventilation, the door between the housing unit and garage must be in place.
Before measurement:
- Close all windows and doors carefully.
- Do not heat the fireplace for about 24 hours before measurement, because the person conducting the measurement will seal the flue with tape or a rubber sealing ball.
- If the building is cold, turn the heater on 24 hours before the measurement, for example. The aim is to create a temperature difference between the interior and exterior, so that the leak points can be detected with a thermographic camera.
- Move construction supplies, furniture and other movables that you can reasonably relocate to a distance of about 1 metre from the wall to facilitate leak detection.
- Arrange sufficient overall lighting for the building to ensure visibility for the measurement.
During measurement:
- Set aside 3–4 hours for the measurement. Other work can continue for the majority of this period.
- It is recommended to arrange for a carpenter to be available on site for any necessary repairs.