Foundation Inspection: Pass on First Try

The foundation inspection is one of the most critical in your entire build.

Get this wrong and you'll have problems for the life of the house. Get it right, and you're building on solid ground—literally.

Here's everything you need to know to pass on the first attempt.

⚠️The Cardinal Rule

NEVER backfill before inspection. This is the #1 failure point. Once backfilled, you'll have to excavate the entire perimeter at a cost of $2,000-$5,000. Mark your calendar. Put up signs. Tell your excavator. DO NOT BACKFILL.

When to Schedule

Timing: After foundation walls are complete but BEFORE backfilling

Critical: You must call for this inspection before any backfill. Once backfilled, the inspector can't verify the foundation exterior.

Notice required: 24-48 hours typically

💡Pro Scheduling Tip

Schedule for early in the week (Tuesday-Wednesday). This gives you time to fix issues before the weekend if you fail, keeping your project on track.

What the Inspector Checks

Foundation Walls

Concrete strength:

Minimum 2,500 psi (3,000 psi in many areas)
Check ready-mix tickets
Inspector may require certified mix design

Wall thickness:

Minimum 6" for 1-story
Minimum 8" for 2-story
Must match approved plans

Height above grade:

Minimum 6" from finished grade to wood framing
Many jurisdictions require 8"
More in high-termite areas

Vertical and plumb:

Walls must be relatively plumb
Excessive bow or lean will fail
Typically max 1" in 8' allowed

Footings

Size and depth:

Minimum width per code (typically 16" for 1-story, 20" for 2-story)
Depth below frost line (varies by location)
Thickness (minimum 8" typical)

Reinforcement (if required):

Rebar size and spacing
Proper placement (not sitting on ground)
Tied properly at corners
Continuous around perimeter

Bearing on undisturbed soil:

No loose soil, mud, or water in footing trench
No organics (roots, stumps, debris)
Soil type matches soil report

Anchor Bolts

Size: 1/2" diameter minimum (5/8" in high-wind or seismic zones)

Spacing:

Maximum 6' on center
Within 12" of plate ends
Within 12" of each side of joints

Embedment: Minimum 7" into concrete

Thread exposure: Enough thread above nut for full engagement (typically 1/2")

Location: Centered in sill plate area

Waterproofing and Drainage

Dampproofing (below grade):

Applied to exterior walls
Continuous from footing to grade
Type depends on soil conditions

Drainage system:

Perimeter drain tile at footing
Proper slope away from foundation
Daylight or connection to sump

Gravel backfill:

Clean gravel around drain tile
Filter fabric over gravel
Prevents clogging

Sill Plate Area

Termite barrier (if required):

Metal termite shield
Borate-treated sill plate
Depends on termite zone

Gasket or sealant:

Foam sill sealer
Sealant under sill plate
Required for energy code in most areas

Proper surface:

Top of foundation level
Anchor bolt holes properly located
Clean of debris

Penetrations and Sleeves

Proper sleeves:

Plumbing penetrations
Electrical conduits
HVAC penetrations
Sized appropriately

Location:

Not in structural weak points
Proper height
Match approved plans

Reinforcement (if required)

Vertical rebar:

Size per plans
Spacing per code
Lap splices proper length
Tied to footing rebar

Horizontal rebar:

Top and bottom as required
Proper cover (typically 3" minimum)
Continuous around corners

Before the Inspector Arrives

Site Preparation - Before Inspector Arrives

Foundation walls complete and cured (typically 3-7 days)

All anchor bolts installed correctly - COUNT THEM

Dampproofing applied (if below grade)

Drain tile installed with proper slope

Gravel around drain tile in place

NO BACKFILL - Verify entire perimeter is open

Foundation clean of excess concrete or debris

Good access all around foundation

Proper lighting if needed

Ready-mix tickets on site

Approved plans on site

Permit posted visibly

You will be present for inspection

Clear recent snow from foundation

Pump out any water in excavation

Notebook and camera ready

During the Inspection

Checks Permit and Plans

Verifies permit is posted and approved plans are on site

Walks Perimeter

Checks wall dimensions match plans, walls are plumb, height above grade is adequate

Inspects Footings

Verifies width and depth, checks reinforcement if visible, inspects excavation condition

Counts Anchor Bolts

Measures spacing (max 6' OC), checks embedment (min 7"), verifies location

Checks Waterproofing

Inspects dampproofing application, drain tile installation, gravel placement

Inspects Penetrations

Verifies sleeves properly installed, top of wall is level, special details from plans

Reviews Paperwork

Checks ready-mix tickets for proper concrete strength, any required certifications

💡Your Role During Inspection

Walk with the inspector - Don't disappear
Answer questions honestly - They appreciate transparency
Take detailed notes on any issues
Don't make excuses - Just acknowledge and plan to fix
Thank them for their time - Build a good relationship

Top 15 Failure Points

Based on a multitude of foundation inspections:

1. Backfilled Before Inspection

Failure: Owner backfilled to "get ahead" before inspection

Code requirement: IRC R401.3 - Inspector must see foundation exterior

Fix: Excavate entire perimeter. Expensive and embarrassing.

Cost: $2,000-$5,000 excavation + delay

Prevention: NEVER backfill before inspection. Mark your calendar. Put up signs. Tell excavator NOT to backfill.

2. Anchor Bolts Spaced Too Far

Failure: Bolts at 7-8' spacing when 6' max required

Code requirement: IRC R403.1.6 - 6' maximum spacing

Fix: Drill and epoxy additional anchor bolts

Cost: $300-$800 + 1-3 days delay

Prevention: Mark bolt spacing on forms before pour. Count off 6' maximum.

3. Insufficient Bolt Embedment

Failure: Bolts only 4-5" deep when 7" minimum required

Code requirement: IRC R403.1.6 - 7" minimum embedment

Fix: Drill and install new epoxied bolts, cut off old ones

Cost: $500-$1,500 + 3-7 days delay (epoxy cure time)

Prevention: Use bolt template. Verify depth during pour with a tape measure.

4. Foundation Too Close to Grade

Failure: Only 4" from grade to sill plate when 6" minimum required

Code requirement: IRC R401.3 - 6" minimum (8" in many areas)

Fix: Raise foundation walls, or lower grade significantly

Cost: If too low: $5,000-$15,000 to add height. Usually must demo and repour.

Prevention: Verify grade elevations before pour. Account for finish grade, not rough.

5. No Dampproofing

Failure: Forgot to dampproof below-grade walls

Code requirement: IRC R406.1 - Dampproofing required

Fix: Apply dampproofing before backfill

Cost: $500-$2,000 + 2-3 days delay

Prevention: Apply dampproofing before calling for inspection.

6. Missing or Improper Drain Tile

Failure: No perimeter drain installed

Code requirement: IRC R405.1 - Drainage required

Fix: Excavate, install drain tile and gravel

Cost: $2,000-$6,000 + 1-2 weeks delay

Prevention: Install drain tile at footing level before backfill. Verify slope.

7. Bolts Too Close to Edge

Failure: Anchor bolts within 1" of foundation edge

Code requirement: Minimum 2" from edge (typ), centered in sill plate

Fix: Drill and install new bolts in correct location

Cost: $300-$800 + delay

Prevention: Center bolts in sill plate area (typically 3-4" from edge).

8. Missing Bolts Near Corners

Failure: No bolt within 12" of plate ends/corners

Code requirement: IRC R403.1.6 - Within 12" of ends

Fix: Drill and epoxy additional bolts

Cost: $200-$500 + delay

Prevention: Mark corners and measure 12" for bolt placement.

9. Footing Too Shallow

Failure: Footing 18" deep when frost line is 36"

Code requirement: IRC R403.1.4 - Below frost line

Fix: Demolish and repour. No alternative.

Cost: $8,000-$20,000 + major delay (3-6 weeks)

Prevention: Know your frost depth. Verify before pouring. Stakes at proper depth.

10. Foundation Not Level

Failure: Top of foundation varies more than 1/2" over length

Code requirement: Must be reasonably level for framing

Fix: Grind down high spots, shim low spots, or pour mud-sill

Cost: $500-$2,000 depending on severity

Prevention: Use laser level during pour. Screed carefully. Check before concrete sets.

11. Wrong Concrete Strength

Failure: 2,000 psi mix when 2,500 psi required

Code requirement: IRC Table R402.2 - Minimum 2,500 psi

Fix: Usually requires structural engineer evaluation. May require replacement.

Cost: $2,000 engineer fee minimum. Potentially $15,000-$50,000 for replacement.

Prevention: Verify mix design before pour. Keep ready-mix tickets.

12. Honeycomb or Voids in Concrete

Failure: Significant voids or honeycomb in walls

Code requirement: Concrete must be solid, properly consolidated

Fix: Epoxy injection for small areas. Demolish and repour for major issues.

Cost: $500-$3,000 for epoxy. $5,000-$20,000+ for replacement.

Prevention: Proper vibration during pour. Don't use mix that's too dry.

13. Missing Reinforcement

Failure: No rebar in walls or footings when required by plans

Code requirement: Per approved structural plans

Fix: Usually requires engineer evaluation. May need to demolish.

Cost: $2,000+ for engineering. Potentially $10,000-$30,000+ for rebuild.

Prevention: Follow approved plans exactly. Double-check rebar before pour.

14. Improper Drainage Slope

Failure: Ground slopes toward foundation

Code requirement: IRC R401.3 - 6" drop in 10' away from foundation

Fix: Regrade after backfill

Cost: $1,000-$3,000 for regrading

Prevention: Plan finish grade before foundation. Verify with stakes and string line.

15. Penetrations Not Sleeved

Failure: Plumbing or electrical penetrations without proper sleeves

Code requirement: Penetrations must allow for movement, prevent water intrusion

Fix: Core drill and install sleeves, patch around pipe

Cost: $500-$1,500 per penetration

Prevention: Install proper sleeves before pour. 2-4" larger than pipe typically.

If You Fail

Don't Panic

Foundation inspection failures are common, even for professionals. Most are fixable.

Get Specifics

What exactly failed?
Code reference?
How to fix correctly?
Can I fix or need professional?
Timeline for re-inspection?

Common Fixes and Costs

Common Foundation Inspection Fixes
Issue	Typical Fix	Cost	Time
Missing anchor bolts	Drill and epoxy bolts	$300-$800	3-7 days
No dampproofing	Apply dampproofing	$500-$2,000	2-3 days
No drain tile	Install drainage system	$2,000-$6,000	1-2 weeks
Foundation too low	Grade down or rebuild	$2,000-$15,000	1-6 weeks
Footing too shallow	Demolish and repour	$8,000-$20,000	4-8 weeks
Wrong concrete strength	Engineer eval/possible replace	$2,000-$50,000	2-12 weeks

Re-Inspection Process

Make ALL corrections (don't skip any items)
Document fixes with photos
Call for re-inspection
Be present again
Show inspector what you fixed

Timeline: Most re-inspections scheduled within 2-3 days for simple fixes.

Cost of Delay

Every day your foundation inspection is delayed costs money:

Equipment rental: $200-$500/day (excavator, laser, etc.)
Subcontractor delays: Framers scheduled but can't start
Interest on construction loan: $50-$150/day
Extended site security/insurance: $20-$50/day

⚠️Real Cost of Delays

A one-week delay = $2,000-$5,000 in holding costs

Prevention is way cheaper than delays. Count your anchor bolts the day before inspection. Verify no backfill. These simple checks save thousands.

Foundation Types: Special Considerations

Poured Concrete

Most common inspection points:

Bolt spacing and embedment
Wall thickness and height
Reinforcement (if required)
Proper mix strength
Dampproofing and drainage

Block (CMU)

Additional checks:

Properly filled cells
Bond beam with reinforcement
Vertical reinforcement in cells
Cap blocks grouted
Proper mortar joints

Permanent Wood Foundation (PWF)

Specific requirements:

Pressure-treated lumber (proper treatment level)
Proper fastener schedule
Vapor barrier installation
Gravel drainage
Foundation-grade plywood

Slab-on-Grade

Different inspection (before concrete pour):

Gravel base thickness and compaction
Vapor barrier (6-mil minimum)
Reinforcement placement
Perimeter insulation (if required)
Plumbing rough-in complete

Regional Variations

High-Wind Areas

Additional requirements:

Larger anchor bolts (5/8")
Closer spacing (4' OC)
Hurricane straps/hold-downs
Engineered foundation design

Seismic Zones

Additional requirements:

Continuous foundation
Proper reinforcement
Hold-downs at shear walls
Anchorage for concentrated loads

Flood Zones

Different requirements:

Elevated foundation
Flood vents
Flood-resistant materials
Proper elevation certification

High Water Table

**Additional requirements