Crack Checker

1. Where is the crack?

Poured concrete foundation or basement wallConcrete block or brick foundation wallBasement floor, slab or garage floorInside wall (drywall or plaster)CeilingOutside wall (brick, stucco or siding)Driveway, patio, sidewalk or pool deck

2. Which way does it run?

VerticalHorizontalDiagonalStair-step in brick or blockSpiderweb or random hairlinesAlong a seam or where wall meets ceiling

3. How wide is it at its widest point?

Measure with a crack gauge or ruler if you can. A standard credit card is about 1/32" (0.76 mm) thick.

Hairline (under 1/16"): a credit card won't go in1/16" to 1/8": a credit card slides in1/8" to 1/4"Wider than 1/4": a pencil tip fits in

4. Do you notice any of these? (tick all that apply)

It's getting longer or widerOne side is higher or sticks out (displaced)The wall bows, leans or bulges, or the ceiling sagsWater seeps through itDoors or windows nearby stick or have new gapsSeveral new cracks appeared recently

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How the checker decides

It weighs the same things inspectors look at first:

• Location: a crack in a load-bearing foundation wall matters more than one in a driveway.
• Direction: horizontal cracks in foundation walls and stair-step cracks in masonry are more concerning than vertical hairlines.
• Width: under 1/16" is usually cosmetic. Over 1/4" usually deserves a professional look.
• Movement: growth, displacement, bowing and sticking doors suggest the structure is still moving, which matters more than width alone.

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How to measure a crack

• Use a crack width gauge (an inexpensive plastic card) or a ruler with 1/16" markings, and measure the widest point.
• No gauge? A standard credit card is about 1/32" (0.76 mm) thick. If it won't slide in, the crack is a hairline.
• Pencil a mark at each end, write the date, and take a photo with a ruler beside it. Comparing photos over weeks and months tells you if the crack is active.

Learn more about your crack