Trade walkthroughs
How to inspect the building envelope
The building envelope keeps air and water out, and it only works if it's continuous. A single break — an unlapped flashing, a gap where the air barrier meets a window, a missed transition membrane — is where the wall leaks and where energy escapes. Inspecting the envelope means chasing continuity through every plane, penetration, and transition before the cladding covers it.
For the superintendent or envelope QC lead verifying the water-resistive barrier, air barrier, and flashings against the details before cladding goes on.
Step by step
Confirm the mock-up sets the standard
Where a mock-up or first-article assembly was built and tested, use it as the accepted benchmark for materials, laps, and workmanship. Every field condition should match what the mock-up proved.
Verify the water-resistive barrier and laps
Check that the WRB is the specified product, installed shingle-fashion with laps meeting the minimum, and fastened or adhered per the spec. Reverse laps and gaps are exactly where water gets behind the cladding.
Trace the air barrier for continuity
Follow the air barrier as a continuous plane and confirm it's tied to the roof, foundation, windows, and every transition. Note every termination and penetration — the air barrier is only as good as its worst joint.
Inspect flashing at openings and transitions
At windows, doors, and every material change, verify flashing sequence, sill pans, end dams, and that head flashing laps over the sides and the WRB laps over the head. This is where most envelope leaks start.
Check penetrations and terminations
Every pipe, conduit, hose bib, and support that pierces the wall has to be flashed and sealed into the barrier. Confirm boots, collars, and transition membranes are continuous with the surrounding barrier, not just caulked over.
Verify vapor control and insulation continuity
Confirm the vapor barrier is on the correct side for the climate and continuous, and that exterior insulation and its joints don't break the barrier plane. Gaps in continuous insulation become thermal bridges and condensation points.
Inspect sealant joints and dissimilar-material transitions
Check joint prep, backer rod, and sealant tooling at cladding joints and transitions, and confirm the right sealant for each substrate. A sealant joint with no backer rod or a three-sided bond fails early.
Test, document, and hold for cover
Where water or air testing is specified, confirm it's run and passed on representative areas, photograph barrier continuity and flashings before cladding, and hold any area with an open break until it's corrected.
What gets missed
- Treating the envelope as separate trades' work instead of one continuous air-and-water system.
- Reverse-lapped WRB or flashing that channels water behind the cladding instead of shedding it.
- Caulking over a penetration instead of flashing it into the barrier plane.
- Breaking the air barrier at transitions to the roof, slab, and windows and never tying it back together.
- Covering the barrier with cladding before continuity and any required testing are documented.
Questions people ask
- What's the difference between the air barrier and the water-resistive barrier?
- The water-resistive barrier sheds bulk water; the air barrier stops air movement through the assembly. One product can do both, but they're different jobs — inspect each for its own kind of continuity.
- Why inspect the envelope before the cladding goes on?
- Because the barriers, flashings, and transitions all get covered by the cladding. Once brick, panel, or siding is up, you can't see whether a lap was reversed or a transition was sealed — so the continuity check has to happen first.
Terms worth knowing
Checklists that make this a one-tap job
Free, field-ready checklists, each with the photo every item needs before it can be submitted.
Related guides
- 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 a roofWalk a roof the way it goes together — deck, dry-in, flashing, penetrations, edge metal — and catch the leaks at the details before they're covered.
- 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.
Reading the steps is one thing. Proving you walked them 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.