An airtightness strategy for a house extension

• Consider the appointment of an independent airtightness adviser.

• Appoint an air barrier manager.

• Identify the line of the air barrier at an early stage of design.

• Inform the project teams of the importance of the air barrier.

• Refer to airtightness in all contracts which impact on the air barrier.

• Specify and/or select airtight components.

• Check interfaces between components and work packages to ensure the continuity of the air barrier.

• Inform the site management team of the location and importance of the air barrier.

• Explain to site operatives the critical importance of airtightness.

• Check air barrier completeness before it becomes impossible to access.

• Schedule an airtightness test by a competent body well in advance.

• A pre-test visit to site by the testing body is recommended for larger sites.

• Ensure all airtightness works are complete.

• Contractor to have responsibility for sealing vents and open flues, closing trickle vents, external doors and windows, in preparation for airtightness test.

• Airtightness test carried out and results issued.

• Results submitted to Building Control/client by contractor.