Foundation Inspection
Before pouring concrete, a building inspector must verify that your foundation meets code requirements. This critical inspection checks rebar placement, anchor bolt locations, form dimensions, and utility stub-outs. Never pour concrete without inspector approval—you may be forced to demolish and start over.
Quick Summary
Time needed
30-60 minutes
Inspection fee
Included in permit
Key contact
Building inspector
Do NOT Pour Without Approval
Pouring concrete before inspection approval is a serious violation. If the inspector finds issues after concrete is poured, you may be required to demolish and rebuild the foundation—adding $10,000-30,000+ to your project and weeks of delays.
What Inspectors Check
Footing Dimensions
Footings must match your approved plans exactly:
- • Width (typically 12-24" depending on loads)
- • Depth (minimum 6-8" for residential)
- • Depth below grade (to frost line in cold climates)
- • Soil bearing surface (undisturbed native soil)
Common issue: Excavating too deep and backfilling creates unstable bearing. Over-excavation may require engineered fill or deeper footings.
Rebar Placement
Reinforcing steel must be properly positioned and secured:
- • Bar size matches plans (typically #4 or #5)
- • Proper spacing (usually 12-18" on center)
- • Adequate concrete cover (3" from soil, 1.5" from forms)
- • Bars elevated on chairs/dobies (not resting on ground)
- • Proper lap splices (40 bar diameters minimum)
- • Corner reinforcement and dowels
Tip: Use rebar chairs (dobies) to maintain proper clearance from ground. Wiring rebar intersections keeps everything in place during pour.
Anchor Bolts
Anchor bolts connect the wood framing to the foundation:
- • Proper size (typically 1/2" or 5/8" diameter)
- • Correct spacing (max 6 feet apart, varies by seismic zone)
- • Minimum 7" embedment depth in concrete
- • 12" maximum from corners and splices
- • Positioned 1.25-1.75" from foundation edge
- • Hold-downs at engineered locations (check plans)
Seismic zones: California and other high-seismic areas require additional hold-down anchors at specific locations. These must match your structural plans exactly.
Forms and Dimensions
Concrete forms define the foundation shape and must be accurate:
- • Forms match plan dimensions (+/- 1/4")
- • Square corners (diagonal measurements match)
- • Forms plumb and level
- • Adequate bracing to withstand concrete pressure
- • Proper stem wall height above grade (varies by code)
- • Clean forms, free of debris
Utility Penetrations
All utility stub-outs must be in place before the pour:
- • Water supply stub-up location and height
- • Drain/sewer stub-out position
- • Electrical conduit penetrations
- • Gas line entry (if applicable)
- • Sleeves properly sized and positioned
Note: Moving utilities after concrete is poured requires core drilling ($300-800 per hole) and may require engineering approval.
Site Conditions
General site conditions that inspectors verify:
- • No standing water in excavation
- • No mud or loose soil at bearing surface
- • Proper setbacks from property lines
- • Erosion control measures in place
- • Approved plans and permits on site
The Inspection Process
Schedule the Inspection
Call your building department 24-48 hours before you need the inspection. Most departments offer morning or afternoon windows. Concrete trucks are scheduled by the hour, so coordinate timing carefully.
Prepare for the Inspector
Have these items ready when the inspector arrives:
- • Approved plans on site (required)
- • Permit card posted and visible
- • Tape measure for verification
- • Clear access to all areas of foundation
- • Someone who knows the project (GC or owner)
During the Inspection
The inspector will walk the site measuring and verifying:
- • Spot-check dimensions against plans
- • Verify rebar size and spacing
- • Check anchor bolt positions
- • Ensure proper clearances
- • Note any deficiencies
Typical duration: 30-60 minutes depending on foundation complexity.
After the Inspection
You'll receive one of three results:
- Approved: You can proceed with the concrete pour. Schedule delivery and proceed.
- Approved with Conditions: Minor fixes needed before pour. Make corrections and you may or may not need re-inspection.
- Failed/Correction Required: Significant issues found. Make corrections and schedule re-inspection before pouring.
Common Issues That Cause Failures
Missing or Wrong Anchor Bolts
Most common failure. Anchor bolts in wrong locations, wrong size, or wrong embedment depth. Double-check your structural plans for exact positions of all anchors and hold-downs.
Rebar Not Elevated
Rebar sitting on dirt instead of chairs. Rebar must have 3" of concrete below it when in contact with soil. Buy enough rebar chairs and use them.
Footing Width Insufficient
Trench walls caved in making footings narrower than plans require. Re-excavate to proper width or install forms to maintain dimensions.
Standing Water in Excavation
Cannot pour concrete into water. Pump out water and allow soil to dry, or add drainage provisions. May need to call for re-inspection.
Utility Sleeves Missing
Forgot to install sleeves for utilities. Core drilling after pour is expensive ($300-800) and may hit rebar. Always install sleeves before inspection.
Pre-Inspection Checklist
Walk through this checklist before calling for inspection:
Frequently Asked Questions
What if I need to reschedule the concrete truck?
Call the concrete company immediately if inspection fails or runs late. Most companies charge $100-200/hour for truck standby time. It's better to reschedule than pour into an unapproved foundation.
Can I fix issues and pour the same day?
For minor issues (adding a chair, tightening a bolt), the inspector may approve on the spot. For significant issues (moving anchor bolts, adding rebar), you'll likely need a re-inspection. Ask your inspector what's acceptable.
What's the next inspection after foundation?
After pouring and curing (typically 7 days), you'll proceed to framing. The next inspection is typically a "framing" or "rough frame" inspection after walls, roof, and sheathing are complete.
Do I need a special inspection for the concrete?
In some jurisdictions, especially for engineered foundations, a "special inspector" (independent of the building inspector) may be required to observe the pour and test concrete cylinders. Check your permit conditions.
Ready for the Next Step?
Once your foundation inspection passes and concrete is poured and cured, you're ready to begin framing your ADU structure. This marks the transition from Site Work to the Structure phase.