- When
- Before the blow, or before foam
- The boundary
- The ceiling, not the roof
- Zone 1 house test
- 7 ACH50, whole house
- What we do not promise
- A blower-door number from bags alone
Why holes beat R-value
Insulation slows heat moving through the material. It does not stop air moving through a gap. In these houses the pressure from the air conditioner, the bath fans, and the wind drives room air into the attic through every unsealed penetration.
That air is cool and dry when the air conditioner has been running, and then the attic is hot and humid. The mix lands on the roof deck and the ducts. Sealing the ceiling cuts that loop. Adding another two inches of fiberglass on top of an open hole does not.
What gets sealed
The top plate of every wall we can reach. Wire and pipe holes. Open chases over showers and cabinets. The attic hatch, weatherstripped, with an insulated cover. Pull-down stairs get a cover, because the stair itself is a thin panel.
Can lights that are not rated for contact get a listed cover or a new fixture. They do not get buried. Bath fans get checked for a duct that actually leaves the building. A fan blowing into the attic stays a problem no matter what R-value goes around it.
Soffit vents stay open. We baffle them. Sealing a soffit to 'tighten the attic' kills the ventilation the roof was built with.
What a blower door is, and is not
Zone 1's tested air-leakage limit for a new house is 7 air changes per hour at 50 pascals. That test covers windows, doors, the garage wall, and every other surface. An attic sealing crew did not just pass that test.
We will not print a number we did not measure. If you want a blower door, that is its own visit. The sealing we do is the visible work at the ceiling, and you can look at it from the hatch before the insulation covers it.