QII Wall Insulation Inspection: What the ECC-Rater Checks Before Drywall
Under quality insulation installation the ECC-Rater walks the framed walls twice: first for the sealed air barrier, then for insulation that fills every cavity without gaps, voids or more than 30 percent compression. The installer must have the signed Insulation Certificate of Installation on site, or the rater cannot give credit.
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Stage one: the air barrier, before any insulation
QII verification is split into a framing stage and an insulation installation stage, each with its own registry document (CF3R-ENV-21-H and CF3R-ENV-22-H). The air barrier must be verified before insulation goes in. Stud cavities are caulked, foamed or otherwise sealed to a substantially airtight envelope against the outdoors, attic, garage and crawl space. Wiring and plumbing penetrations through the top and bottom plates are sealed, as are electrical boxes that go through the sheathing, and bottom plates are sealed to the subfloor or slab.
Stage two: what fills the cavity
Batts must reach side to side, top to bottom and front to back, touching the sheathing behind and the wallboard in front. Around wiring and plumbing they are cut to butt-fit or split, one layer behind the obstruction and one in front. Flanged batts that are inset-stapled may leave a void, but only within 2 inches of the stud. Compression around vents, pipes and other obstructions may not exceed 30 percent of nominal thickness.
Measuring what was installed
- The rater verifies installed thickness in every assembly.
- For loose-fill, the rater measures thickness and density at no fewer than 6 random locations per surface type and compares density with the manufacturer's coverage chart.
Paperwork that decides the result
A signed Insulation Certificate of Installation with the product data sheet, bag label or coverage chart attached must be on the job site at every verification visit. The appendix is direct about it: the rater cannot verify compliance credit without those completed forms.
Why it matters on a performance report
QII is not a mandatory measure. Compliance software assumes it in the standard design and reduces insulation effectiveness for a proposed design that does not pursue it, so a performance design can trade it off. Where it is required is on the QII overview; the attic list is on the QII attic page. Wall U-factors are covered on wall insulation and what an ECC-Rater does explains the role. Order a residential report before framing so the plan matches the walls.
Common Title 24 Questions
- When is Title 24 required for a home?
- Does a remodel need Title 24?
- Does a room addition need Title 24?
- What plans are needed for a residential Title 24 report?
- How much does a residential Title 24 report cost?
- How long does a residential Title 24 report take?
Frequently Asked Questions
Not for the air barrier. The manual says it must be verified before insulation is installed, so the framing stage cannot wait until the walls are closed in.
Insulation is placed between the sheathing and the back of any box or obstruction that is not as deep as the cavity, such as a communications box or medicine cabinet.
Explore Insulation
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View all Insulation guides → · Windows and Building Envelope · Title 24 guide