Insulation Inspection: Pass on First Try

The insulation inspection verifies your home meets energy code requirements.

This is where air sealing, insulation R-values, and thermal envelope integrity are checked. Pass this and you'll have a comfortable, energy-efficient home.

ℹī¸Important Information

This inspection must happen after insulation is installed but BEFORE drywall. Once you drywall, the inspector can't verify insulation quality or air sealing.

When to Schedule

Timing: After insulation is installed but BEFORE interior wall covering (drywall)

Critical sequence:

  1. Rough-in inspections passed (electrical, plumbing, HVAC)
  2. All insulation installed in walls, ceilings, and floors
  3. Air sealing complete
  4. Vapor barriers installed where required
  5. NO drywall or interior finish installed yet

Notice required: 24-48 hours typically

My pro tip: This inspection often gets skipped or combined with final inspection in some jurisdictions. Ask your building department. If required as separate inspection, schedule it promptly after insulation is complete - don't delay.

Weather consideration: Interior inspection, so weather rarely delays it.

Special note: Some jurisdictions use blower door testing or thermal imaging. Ask beforehand what testing methods will be used.

What the Inspector Checks

Energy Code Compliance

Applicable code: IRC Chapter 11 (N1101-N1107) and local amendments

Climate zone: Your requirements depend on climate zone (check IRC Figure N1101.7 or ask building department)

Compliance path:

Key concept: The thermal envelope must be continuous with minimal gaps or voids.

Insulation R-Values

Walls (IRC Table N1102.1.3):

Ceilings/Attics (IRC Table N1102.1.3):

Floors over unconditioned space (IRC Table N1102.1.3):

Basement walls (IRC Table N1102.1.3):

Crawl space walls (IRC Table N1102.1.3):

Foundation details:

Insulation Installation Quality

Wall insulation:

Ceiling/attic insulation:

Floor insulation (over crawl/basement):

Basement/crawlspace insulation:

Air Sealing (Critical!)

Concept: Air leakage wastes more energy than missing insulation. Inspector focuses heavily on this.

Key air sealing locations (IRC N1102.4.1):

Air sealing materials:

Blower door test (if required):

Vapor Barriers and Retarders

Vapor retarder required (IRC N1102.5):

Not required:

Installation:

Common mistake: Installing vapor barrier in climate where it causes moisture problems. Check your climate zone requirements.

Windows and Doors

U-factor requirements (IRC Table N1102.1.3):

Skylight U-factor:

SHGC (Solar Heat Gain Coefficient):

Installation:

Documentation: Be ready to show window labels proving U-factor compliance.

Duct Insulation

Ducts in unconditioned spaces (IRC N1103.3.3):

Supply ducts:

Return ducts:

Common issue: Ducts in vented attic or crawlspace not insulated.

Recessed Lighting

IC-rated fixtures:

Non-IC fixtures:

Better approach: Use IC-rated, airtight fixtures throughout.

Specific Details Checked

Rim joist/band joist:

Cantilevered floors:

Dropped soffits and chases:

Kneewalls (attic):

Attic access:

Whole-house ventilation:

Before the Inspector Arrives

48 Hours Before Insulation Inspection

Self-Inspection Walk-Through - Complete Before Calling

💡Pro Tip

Use flashlight: Shine from different angles to see gaps or voids you'd otherwise miss.

Use phone camera: Take photos from different angles - it's often easier to see issues in photos than with naked eye.

During the Inspection

Inspector's Typical Route

  1. Reviews documentation: Energy code compliance method, window U-factor labels
  2. Attic: Checks depth, coverage, baffles, air sealing
  3. Walls: Spot-checks for voids, compression, air sealing
  4. Floors/rim joists: Checks for gaps and proper installation
  5. Special details: Recessed lights, attic access, penetrations
  6. Thermal imaging (if used): Scans for air leakage and missing insulation
  7. Blower door test (if required): Tests overall air tightness

Timeline: Expect 30 minutes to 1.5 hours depending on house size and testing required.

Your role:

Bring:

Top 15 Failure Points

1. Insulation Voids and Gaps

Failure: Missing insulation in cavities, gaps around boxes, or incomplete coverage

Code requirement: IRC N1102.4.2 - Insulation shall provide continuous thermal barrier

Common locations:

How to fix: Fill all voids with insulation, split batts around obstacles

Time to re-inspect: 1-3 days

Cost: $200-$600 (labor to add insulation)

Prevention: Take time to insulate completely, split batts around obstacles, use pieces to fill small gaps

Inspector tip: They use thermal imaging cameras - voids show up clearly as cold spots.

2. Compressed Insulation

Failure: Insulation compressed, reducing effective R-value

Code requirement: IRC N1102.4.2 - Must achieve rated R-value

How it happens:

How to fix: Remove and reinstall with proper thickness, don't compress

Time to re-inspect: 2-4 days

Cost: $300-$800 (labor to redo insulation)

Prevention: Use correct insulation thickness for cavity depth, don't compress to fit

3. Missing Air Sealing

Failure: Penetrations and gaps not sealed with foam or caulk

Code requirement: IRC N1102.4.1 - Thermal envelope shall be sealed

Critical locations often missed:

How to fix: Seal all penetrations with appropriate material (foam, caulk, gaskets)

Time to re-inspect: 2-4 days

Cost: $300-$1,000 (labor and materials for extensive air sealing)

Prevention: Air seal as you go, don't wait until end, use foam for gaps, caulk for small cracks

This is critical: More important than insulation R-value in many ways.

4. No Baffles at Eaves

Failure: Missing ventilation baffles at attic eaves

Code requirement: IRC N1102.2.3 - Maintain ventilation while insulating

Why required:

How to fix: Install baffles at each rafter bay

Time to re-inspect: 1-2 days

Cost: $150-$400 (baffles and labor)

Prevention: Install baffles before blowing or laying insulation

5. Recessed Lights Not Properly Treated

Failure: Non-IC lights in contact with insulation, or non-airtight lights without sealing

Code requirement: IRC N1102.4.4 - Recessed lights must be IC-rated airtight, or sealed box with clearance

Issues:

How to fix: Replace with IC-rated airtight fixtures, or build proper clearance box

Time to re-inspect: 3-5 days (electrical work)

Cost: $300-$1,200 (replacing fixtures or building boxes)

Prevention: Use only IC-rated airtight recessed lights, or avoid recessed lights in insulated ceilings

6. Insufficient Attic Insulation Depth

Failure: Attic insulation doesn't meet required R-value

Code requirement: IRC Table N1102.1.3 (typically R-38 to R-49 depending on climate)

How to check:

How to fix: Add insulation to achieve required depth

Time to re-inspect: 1-3 days

Cost: $400-$1,500 (additional insulation and labor)

Prevention: Calculate required depth before installation, verify throughout attic, add more if marginal

7. Rim Joist Not Insulated

Failure: Rim joist (band joist) not insulated or air sealed

Code requirement: IRC N1102.4.2 - Must insulate to full wall R-value

Common issue: Often forgotten because framing covers it

How to fix: Insulate rim joist with spray foam or batt insulation, air seal to subfloor and sill plate

Time to re-inspect: 2-4 days

Cost: $400-$1,200 (accessing and insulating rim joist)

Prevention: Insulate rim joist before framing walls, or from exterior before sheathing

Pro tip: Spray foam works best for rim joist.

8. Wrong Vapor Barrier Installation

Failure: Vapor barrier on wrong side, or installed where not appropriate

Code requirement: IRC N1102.5 - Climate-dependent requirements

Common mistakes:

How to fix: Remove incorrect vapor barrier, install correctly if required

Time to re-inspect: 3-7 days (can be extensive)

Cost: $500-$2,000 (removing and reinstalling)

Prevention: Know your climate zone requirements, understand vapor barrier theory, consult with building department

9. Windows Don't Meet U-Factor Requirements

Failure: Windows exceed maximum U-factor for climate zone

Code requirement: IRC Table N1102.1.3

Issue: Can't fix by adding insulation - windows are wrong

How to fix: Replace windows with code-compliant models

Time to re-inspect: 1-2 weeks (ordering and installing windows)

Cost: $3,000-$15,000+ (replacing all windows)

Prevention: Verify window U-factor BEFORE ordering, check against climate zone requirements, keep labels

This is expensive: Order correct windows from the start.

10. Attic Access Not Insulated or Sealed

Failure: Attic access hatch or stairs not insulated and weatherstripped

Code requirement: IRC N1102.2.4 - Access doors shall be insulated and sealed

Requirements:

How to fix: Add insulation to hatch, install weatherstripping, add latches

Time to re-inspect: 1-2 days

Cost: $100-$300 (materials and labor)

Prevention: Insulate and weatherstrip attic access before calling inspection

11. Kneewall Not Properly Insulated

Failure: Kneewall insulation missing, or no air barrier on attic side

Code requirement: IRC N1102.2.10 - Kneewalls must be insulated with air barrier

What's needed:

How to fix: Insulate kneewall, install air barrier, insulate attic floor

Time to re-inspect: 3-5 days

Cost: $500-$1,500 (depends on extent)

Prevention: Plan kneewall insulation strategy, include air barrier, insulate attic floor beyond

12. Cantilevered Floor Not Insulated

Failure: Cantilevered floor section not insulated or air sealed

Code requirement: IRC N1102.2.7 - Cantilevered floors over exterior walls or unconditioned space shall be insulated

What's needed:

How to fix: Access from below and insulate, or remove floor sheathing from above

Time to re-inspect: 3-5 days

Cost: $400-$1,200 (accessing and insulating)

Prevention: Insulate cantilevers from below before closing in, or from above before subfloor

13. Duct Insulation Insufficient

Failure: Ducts in unconditioned spaces not insulated to R-8

Code requirement: IRC N1103.3.3 - R-8 in unconditioned spaces

Common issues:

How to fix: Add insulation to achieve R-8, seal all joints

Time to re-inspect: 2-4 days

Cost: $400-$1,200 (adding duct insulation)

Prevention: Specify R-8 duct insulation in unconditioned spaces, verify installation

14. Blower Door Test Failure

Failure: House too leaky, exceeds maximum ACH50

Code requirement: IRC N1102.4.1.2 - Maximum 3 or 5 ACH50 depending on climate

Common leakage points:

How to fix: Systematic air sealing of all penetrations and joints

Time to re-inspect: 3-7 days (extensive air sealing)

Cost: $500-$2,000 (labor and materials for air sealing)

Prevention: Air seal thoroughly during construction, test yourself with blower door before calling inspection

Consider: Hiring energy auditor to test before official inspection.

15. Garage Separation Not Sealed

Failure: Air barrier between garage and house not complete

Code requirement: IRC N1102.4.1 - Separate conditioned from unconditioned spaces

What's needed:

How to fix: Air seal all penetrations, weatherstrip door, complete insulation

Time to re-inspect: 2-4 days

Cost: $300-$800 (air sealing and weatherstripping)

Prevention: Treat garage wall as exterior wall, air seal thoroughly

If You Fail

Stay Calm

Insulation inspection failures are usually easy to fix - just adding more insulation or air sealing.

Get Specific Details

Ask inspector:

Request infrared images if thermal camera was used - shows exactly where problems are.

Common Fixes and Timeline

| Issue | Fix | Cost | Timeline | |-------|-----|------|----------| | Insulation voids | Fill gaps | $200-600 | 1-3 days | | Insufficient depth | Add insulation | $400-1,500 | 1-3 days | | Missing air sealing | Foam/caulk penetrations | $300-1,000 | 2-4 days | | No baffles | Install baffles | $150-400 | 1-2 days | | Rim joist not insulated | Insulate rim joist | $400-1,200 | 2-4 days | | Attic access not sealed | Insulate and weatherstrip | $100-300 | 1-2 days | | Wrong windows | Replace windows | $3,000-15,000+ | 1-2 weeks |

Re-Inspection Process

  1. Fix all noted issues
  2. Do another self-inspection
  3. Take photos of corrections
  4. Call for re-inspection
  5. Be present to show corrections

Re-inspection timing: Usually 2-3 days

Cost of Delay

Each week insulation inspection is delayed:

One week delay = $800-$2,000

However: Better to delay and do it right than rush and fail.

Special Considerations

Spray Foam Insulation

Advantages:

Inspector focus:

Cost: 2-3x batts but includes air sealing.

Blown-In Insulation

Attic:

Wall:

Rigid Foam Board

Exterior continuous insulation:

**Basement/crawlspace