Thermal Insulation Inspection

Per IECC Table R402.1.2, minimum R-values vary by climate zone: Attic R-38 to R-60, Walls R-13 to R-20+5ci, Floors R-19 to R-38, Basement walls R-10 to R-15. Check local code for your specific climate zone requirements.

1. Verify insulation R-value meets or exceeds local code requirements

2. Measure insulation depth in accessible areas (attic, crawl space)

3. Check insulation label for stated R-value per inch

4. Compare installed depth to required depth for the R-value

5. Verify continuous insulation on exterior if required by code

- Insufficient R-value for climate zone

- Compressed insulation reducing effective R-value

- Missing insulation in difficult-to-access areas

- Mismatch between specified and installed insulation type

Per RESNET standards, insulation must be installed to Grade I quality: filling cavities side-to-side, top-to-bottom, and front-to-back with no gaps, voids, compressions, or missing areas. Grade I installation provides the labeled R-value; Grade II and III significantly reduce performance.

1. Check that insulation fills stud cavities completely — no gaps at top, bottom, or sides

2. Verify insulation is not compressed behind wires or pipes

3. Look for voids around electrical boxes and at framing intersections

4. Verify insulation is in contact with the air barrier on all six sides

5. Check that batt insulation is cut to fit around obstacles, not stuffed

- Gaps at top or bottom of stud cavities

- Insulation compressed behind wiring or plumbing

- Voids around electrical boxes and penetrations

- Missing insulation at rim joists and band boards

Per IECC R402.4, the building thermal envelope must be sealed to limit air leakage. Maximum air leakage rate is 3-5 ACH50 depending on climate zone. All penetrations, joints, and openings in the air barrier must be sealed with caulk, foam, or gaskets.

1. Check sealing around all penetrations (electrical, plumbing, HVAC)

2. Verify top plates are sealed at attic interface

3. Check rim joist area for air sealing

4. Inspect around windows and doors for foam or sealant

5. If available, review blower door test results (should be ≤3-5 ACH50)

- Unsealed penetrations at top plates into attic

- Missing air sealing at rim joists

- Gaps around window and door frames

- Open chases for plumbing or electrical allowing stack effect