Short answer
If your Okanagan build missed its ACH50 target and the flooring, cabinets and trim are not in yet, an AeroBarrier seal can usually bring it down to the target without opening finished walls. The blower door runs during the seal, so the leakage reading falls live and I stop when the house hits the number. Your energy advisor then retests. If the miss is caused by large open holes, those get closed by hand first, and I will tell you straight if a seal will not get you there.
First, read the test result properly
Get the full result from your energy advisor, not just pass or fail. Three numbers matter:
- ACH50: air changes per hour at 50 pascals. This is the airtightness number the Step Code targets are written in.
- CFM50: the measured airflow at 50 pascals. This is the raw leakage the seal has to remove.
- Volume: the conditioned volume the test used. ACH50 is CFM50 times 60, divided by volume. On small units a modest CFM50 can produce a high ACH50, which changes what it takes to pass.
With those I can tell you how much leakage has to come out to hit your target, and whether that is a normal seal or a stretch.
When a rescue seal works
- The miss is diffuse leakage. Most failed tests are not one big hole. They are hundreds of small ones at plates, rim joists, penetrations and drywall edges. That is exactly what the aerosol is built for.
- Finishes are not in yet. Drywall up, taped and primed still works. Flooring, cabinets and trim close the window.
- The house can be closed up. Windows and exterior doors in, so it can hold pressure.
When it will not, on its own
- A large open hole. An unsealed chase, a missing piece of sheathing, an open duct or a fireplace with no damper. Those need hand work first. A seal after that is often what gets you over the line.
- Finished interiors. Once the flooring and cabinets are in, masking is not practical.
- A number that is wildly off. If the result suggests a structural air barrier failure, I will tell you that instead of selling you a seal.
The honest version: I look at the result and the house first, and if a seal is not the right fix I say so.
How the rescue runs
- Send me the energy advisor's result (ACH50, CFM50, volume) and the target step.
- I look at the stage and the house, and flag any big holes that need hand sealing first.
- We book the seal. On the day I take a baseline reading, seal to the target live, and take a closing reading.
- You get an Airtightness Verification Report for your file.
- Your energy advisor retests. Their result is the one for your Step Code compliance file.
Caught at mid-construction, a miss is cheap to fix. Caught at the final test, it is expensive. If your build has not had its mid-construction test yet, book the seal around it. See Step Code airtightness.
What a miss costs if you chase it by hand
A crew hunting leaks by hand burns days with no way of knowing they found enough until the retest. Each retest is another energy advisor visit and another wait. The schedule slips, occupancy waits, and on a project still counting on the FortisBC rebate before it ends on February 28, 2027, the rebate is at risk too. A measured seal replaces that loop with one day and a known result. The cost page has a worksheet to run the comparison on your own numbers.
Written by Sebastian Motora, owner-operator. Last reviewed October 7, 2026.