Field & trade terms
Air barrier
An air barrier is the continuous layer that stops air from passing through the enclosure: sheet, membrane, sealed sheathing or the right combination, joined so it forms one unbroken plane around the conditioned space. Air carries far more moisture and energy than diffusion ever does, so a leaky enclosure both wastes conditioning and drives hidden condensation. Unlike a vapor retarder, which slows diffusion, the air barrier's whole job is continuity: it only works if every joint, seam and hole is sealed.
Run it with the Photo Gate
Insulation inspection checklist
12 items · 26 photos required
How it shows up on site
The air barrier is the taped sheathing seams, the sealed sheet, the transition membranes at slab, roof and openings, and the sealant around every pipe, conduit and duct that punches through. Its weak points are exactly the transitions: where one material hands off to another and where the trades put their holes.
What an inspector looks at
The check is continuity: are seams and laps sealed, are transitions detailed and taped, is every penetration closed, and does the plane actually connect from foundation to roof without a gap left for later. Gaps behind soon-to-be-covered assemblies get the hardest look.
Because RTI closes items on a photo, the air barrier is documented while it's reachable, with sealed seams, transition details and penetration seals shot before cladding, insulation or finishes make them impossible to verify.
Guides that use it
- How to inspect the building envelopeInspect the envelope as a system (air barrier, water-resistive barrier, flashing, transitions, and sealants) with the continuity and mock-up that make it perform.
- How to inspect windows and glazingInspect windows and glazing from rough opening to seal (pan flashing, anchoring, integration with the WRB, and glazing), where water and air most often get in.
- How to inspect insulation before coverInspect insulation and its air and vapor barriers before drywall covers them: coverage, fit, continuity, and the gaps that become thermal and moisture problems.
- How to inspect a curtain wallInspect a curtain wall as a drained system (anchors, framing, gaskets and pressure plates, glazing, and the weep path) against the details and the approved mock-up.
Standards it's verified against
Checklists that put air barrier to work
Free, field-ready checklists, each with the photo every item needs before it can be submitted.
Related terms
- Vapor barrierA sheet material that limits how much water vapor diffuses through an assembly, placed to keep condensation from forming inside the wall or floor.
- FlashingThin sheet material lapped into an assembly to direct water back out at joints, edges and openings before it can get behind the finish.
- PenetrationAny point where a pipe, conduit, duct or cable passes through a wall, floor or roof, leaving a hole that has to be sealed back to match the assembly it crosses.
- Dry-inThe point at which a building is closed to weather: roof, wall barrier and openings sealed enough to keep water out and let interior work start.
- SheathingThe structural panel skin over studs, rafters or joists that braces the frame and gives cladding, roofing and the barrier a base to attach to.
- Thermal bridgeA path of high heat conductivity through the building envelope (a stud, slab edge or metal member) that bypasses the insulation and lets heat short-circuit through.
Knowing the term is step one. Proving it is the job.
RTI holds the submit button until every mandatory item is answered and the photos are attached, then chains the record so it can be proven untouched later.
30-day trial · No card required