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Run a mid-build airtightness test

Testing before linings go on lets you find and fix leaks cheaply. After drywall, leaks are hidden.

How

1. Book a blower door test once the air barrier, windows and doors are in but before insulation is covered.
2. Seal temporary openings and note any missing components; PNNL guidance says to cover gaps for parts not yet installed.
3. Walk the house during depressurisation with a smoke pencil or thermal camera and mark leaks.
4. Seal leaks with tape, gaskets or sealant and retest if far from target.

Sources

1. Enclosure Leakage Test (Building America Solution Center). Pacific Northwest National Laboratory for US DOE, accessed 2026-11
2. Consumer Guide to Air Sealing the Home (DOE/EE-2470). US Department of Energy, Energy Saver, accessed 2026-11

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