The same 10 details cause the vast majority of air leakage failures across Australian construction projects, regardless of building type.
Most of these leaks aren't caused by bad materials, they're caused by trade sequencing and unclear responsibility at junctions between trades.
Service, ceiling, and electrical penetrations are consistently the highest-frequency leak points because so many different trades pass through the same wall.
Catching these details at schematic design and during site audits is dramatically cheaper than finding them on final test day.
Every one of these 10 causes is preventable with the right detailing, sequencing, and a preliminary test before the formal AS/NZS ISO 9972 test.
Run enough blower door tests and a pattern shows up fast: it’s almost never the wall itself leaking. It’s the 10 places where something else, a pipe, a duct, a joint, a shaft, passes through it. These junctions get handed between trades, and air leakage is what happens in the gap between “someone else will seal that” and the final test.
Here are the 10 details that cause the majority of air leakage failures on-site, and what to watch for on your next project.
Every one of these points has one thing in common: two different trades meet at the same junction, and neither one owns the airtightness outcome.
The plumber isn’t thinking about the air barrier. Neither is the electrician, the mechanical contractor, or the façade installer. That’s not a workmanship problem; it’s a coordination problem, and it’s exactly why Aerotight runs project workshops before a single wall goes up.
This junction sits at the intersection of two completely different air barrier systems, wall and roof, usually installed by two different trades on two different schedules. If the two systems aren’t detailed to physically lap and connect, there’s a continuous gap running the length of the building.
Every one of these 10 causes is dramatically cheaper to fix on paper than on-site. Reviewing drawings and defining the air barrier line before construction starts, the second step in Aerotight’s process, catches most of these before a single penetration is cut.
Drawings don’t account for what actually happens when six trades are on-site at once. Site audits during construction, carried out by qualified builders, catch the gap between the detail as drawn and the detail as installed, before it’s buried behind linings.
Service penetrations, pipes, cables, and ducts passing through the envelope, are consistently the highest-frequency leak point, simply because there are so many of them on a typical project.
Yes, but it’s significantly more expensive once penetrations are buried behind finishes. Preliminary testing during construction identifies leaks while they’re still accessible.
No. Fire-stopping products are rated for fire and smoke performance. Achieving both fire compliance and airtightness at the same penetration requires a detail and product suited to both.
Find out which of these 10 details are leaking while they’re still cheap to fix. Book an appointment with Aerotight.
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