Monitoring Wall Cracks

Hotline Question

Do you have any suggestions for monitoring cracks in a concrete wall?

Hotline Answer

The article "Evaluating Cracks in Concrete Walls" (Concrete Construction, January, 1993) describes several methods commonly used.

To determine if the crack is active or relatively dormant, apply a small patch of plaster over the crack. The plaster cracks if the crack is active.

It's a little more difficult if you also need to know how much a crack is moving. If an approximate evaluation is OK, make pencil marks (parallel lines or a "+") on both sides of the crack and measure between them at regular intervals. To be more precise, a crack monitor is needed. The article shows one commonly used device, which is available for $15 from:

Avongard, 2386 Osage, Waukegan, IL 60087 (phone 708-244-4170).

After installing a crack monitor, it's a good idea to make measurements frequently to see if the values are changing. When you become confident in making the measurements and they aren't changing very much you may wish to take them less frequently.

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