How to Identify Foundation Cracks
Foundation cracks range from harmless to serious structural issues. Learn to identify crack types, measure progression, and determine when professional evaluation is needed.
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0 of 6 steps completedStep-by-Step Instructions
1 Step 1: Inspect All Foundation Areas
Step 1: Inspect All Foundation Areas
Check interior basement walls, exterior foundation, and crawlspace. Look for both vertical and horizontal cracks, as well as stair-step patterns in block.
LED Flashlight High Lumens
Powerful flashlight for inspecting dark crawl spaces and basement areas
Inspection Mirror with Light
Telescoping mirror for viewing hard-to-reach foundation areas
Moisture Meter
Digital moisture detector for identifying water intrusion near cracks
2 Step 2: Measure Crack Width
Step 2: Measure Crack Width
Use crack width ruler or coin for comparison. Hairline cracks under 1/16" are usually minor. Cracks wider than 1/4" require professional assessment.
Crack Width Measurement Card
Precision card gauge for measuring foundation crack widths
Digital Caliper
Electronic caliper for precise crack measurement
Crack Monitoring Gauge
Adhesive gauges for tracking crack movement over time
3 Step 3: Identify Crack Patterns
Step 3: Identify Crack Patterns
Vertical cracks are often settling. Horizontal cracks indicate pressure and are serious. Stair-step cracks in block walls suggest foundation movement.
4 Step 4: Check for Active Movement
Step 4: Check for Active Movement
Mark crack ends with pencil and date. Photograph. Measure width. Re-check in 30-60 days to determine if crack is growing.
Waterproof Camera
Inspection camera for documenting foundation cracks in detail
Measuring Tape
Tape measure for recording crack locations and dimensions
Foundation Inspection Notebook
Weatherproof notebook for detailed crack documentation
5 Step 5: Look for Additional Signs
Step 5: Look for Additional Signs
Check for doors/windows that stick, uneven floors, gaps between walls and ceiling/floor, or separation between walls and chimney.
6 Step 6: Get Professional Foundation Inspection
Step 6: Get Professional Foundation Inspection
For cracks wider than 1/4", horizontal cracks, rapid growth, or multiple signs of settlement, hire structural engineer or foundation specialist.