The best time to find QII problems is before the rater arrives. Insulation crews need a deliberate rough-in walkthrough that follows the field details an ECC rater (formerly HERS rater) reviews during a Quality Insulation Installation inspection.

The controlling 2025-code criteria are in the CEC’s Reference Residential Appendix RA3.5. The applicable assembly, project documents, and manufacturer instructions determine the acceptable materials and details.

This walkthrough is written for the people doing the work in the field. It is not a replacement for the approved compliance documents or the rater’s procedure, but it gives crews a practical way to catch gaps, compression, missing air barriers, and documentation problems before they become correction items. Keep the common QII failures guide nearby for examples to discuss during the crew huddle.

Before You Start the Walkthrough

Walk the project after insulation is installed and before drywall. Bring a flashlight, a copy of the insulation scope or energy report if available, and enough material to make quick repairs. If the job is large, assign one person to inspect and one person to fix. A clean QII walkthrough is easier when the crew is not rushing to leave the site.

Start by confirming the inspection conditions:

All insulated cavities are still visible
Rough plumbing, electrical, HVAC, and low-voltage work is complete
Attic, crawl space, and garage access are open
Insulation labels or packaging are available
The installed material matches the specified R-values
Any known framing changes have been communicated to the builder

If other trades are still working in the envelope, tell the superintendent. Insulation installed before rough-ins are complete is much more likely to be damaged before the QII inspection.

Exterior Walls

Exterior walls are where most crews spend the most time, but they still deserve a careful final pass. Look at each wall from top to bottom and bay by bay. The rater will be checking for continuous fill and air barrier contact, not just whether insulation is present.

Check for:

Batts flush with the face of framing
No visible sheathing gaps behind the insulation
No curled edges or tucked corners
No compressed areas around pipes, wires, straps, or boxes
No missing insulation above and below windows
Header areas insulated according to the approved detail
Narrow cavities cut and filled instead of skipped

Use your hand and eyes. If a batt feels springy because it is not touching the sheathing, refit it. If a batt is wider than the cavity and folded at the side, trim it. If a cavity is too small for a standard batt, cut a custom piece. The small fixes are what separate a QII-ready wall from an ordinary insulation job.

Electrical and Plumbing Penetrations

After the wall scan, make a second pass that focuses only on penetrations. This keeps crews from missing issues hidden by visual clutter.

At wires and pipes, insulation should be split around the obstruction so the cavity remains filled on both sides. At electrical boxes, insulation should be cut around the box and fill the space behind it where possible. Around plumbing, do not leave open channels beside supply or drain lines. If there are large pipe clusters, use pieces that fit the actual shape of the cavity rather than forcing one batt around everything.

A useful rule for crews: if the insulation had to be shoved into place, it probably needs to be refit.

Tub and Shower Surrounds

Exterior walls behind tubs and showers are classic QII problem areas because access disappears quickly. These walls need insulation, and they need a durable air barrier before the fixture blocks access. If the tub or shower is already set and the wall behind it is open, check carefully.

Look for:

Full insulation coverage behind the fixture
No open cavities at the corners
Backing or air barrier material where required
No insulation falling away from the exterior sheathing
Clear documentation if the area will be hard for the rater to see

Do not assume the rater will ignore a hidden area. If it is part of the thermal envelope, it matters.

Rim Joists and Floor Transitions

Rim areas can be easy to miss because they are not always in the same visual plane as the walls. Where they are within the project’s thermal boundary, review them for the material, coverage, and air-barrier alignment required by the approved detail.

Check that each rim joist cavity is filled to the required R-value and that the material is secure. Loose scraps stuffed into a rim joist cavity are not the same as a complete installation. If the project uses spray foam at rim joists, verify thickness and full coverage. If it uses batts, cut each piece to fit snugly and keep it in contact with the surface it is insulating.

Pay extra attention where framing changes direction. Corners, joist pockets, dropped beams, and stair openings often create small exposed areas that are easy to overlook.

Garage Separation Walls and Floors Over Garages

Walls between conditioned space and an attached garage are part of the thermal boundary when they separate living space from unconditioned space. Floors over garages need the same level of care. These assemblies often include ducts, pipes, recessed areas, and blocking that make the install harder than a standard wall.

For garage separation walls, verify complete cavity fill and proper fitting around penetrations. For floors over garages, confirm that insulation is in contact with the subfloor above and supported so it does not sag. Sagging floor insulation creates air space above the insulation, reducing performance and inviting QII corrections.

Attics and Roof/Ceiling Assemblies

Attics need a different walkthrough rhythm. Instead of scanning wall bays, check depth, coverage, ventilation clearance, and edge conditions.

For blown-in attic insulation, confirm that depth markers are installed and visible. The insulation should reach the required depth across the attic, including near the eaves. Baffles should maintain ventilation paths without leaving the exterior wall top plates under-insulated. Around can lights, exhaust fans, chases, and attic hatches, insulation should be installed according to code and manufacturer clearances.

For vaulted ceilings, roof decks, or unvented attic assemblies, the crew should verify that insulation is continuous, properly supported, and aligned with the intended air barrier. These assemblies are less forgiving because a missed area may not be visible once interior finishes begin.

Kneewalls, Skylight Shafts, and Framed Bump-Outs

Kneewalls and skylight shafts are common in bonus rooms, attic spaces, and custom homes. If air-permeable insulation is exposed to attic space, the backside needs a continuous air barrier. Without that backing, air can move through or behind the insulation and reduce performance.

Framed bump-outs and double walls need either full cavity fill or an added air barrier that defines the insulated cavity. The crew should not leave a deep framed space partly filled with a batt floating in the middle. The rater needs to see a complete thermal boundary.

These details should ideally be planned before insulation day. If backing is missing, tell the builder before trying to improvise a fix that may not satisfy the inspection.

Trade Damage and Last-Minute Repairs

Before leaving, walk the house once more looking only for disturbed areas. Other trades may have pulled a wire, moved a pipe, opened a cavity, or knocked material loose. Look near panels, mechanical closets, plumbing walls, low-voltage drops, and exterior penetrations.

Repair what you can. Photograph what you repair. If damage is ongoing or another trade needs access, tell the superintendent which walls will need a final touch-up before inspection.

What to Have Ready for the Rater

A QII inspection goes faster when the jobsite is organized. The rater should be able to verify the work without hunting for documents or moving material piles.

Have ready:

Current insulation scope or energy compliance documents
Product labels, bag counts, or coverage information
Access to attic, crawl space, garage, and mechanical areas
Clear paths through rooms and around exterior walls
Someone available by phone who can answer project-specific questions

Good preparation shows the rater that the contractor and builder are taking QII seriously.

A Simple Final Question

At the end of the walkthrough, ask one question in every room: “Can I see a continuous thermal boundary here?”

If the answer is yes, the room is probably close. If the answer is no, find out why. Maybe a cavity is missing insulation. Maybe a batt is compressed behind plumbing. Maybe a kneewall has no backside air barrier. Maybe the attic edge thins out at the eave. QII is detailed, but the underlying principle is straightforward: the building envelope should be insulated continuously and cleanly.

Schedule QII With Poppy Energy

Insulation foremen and superintendents can contact Poppy Energy to schedule rough-in verification or coordinate jobsite access and documentation before the crew leaves.

The QII Rough-In Walkthrough: A Jobsite Guide for Insulation Crews