frost heave on CMU basement wall

PSUengineer1 · Feb 9, 2018

in upper 1/3 of CMU wall I have a horizontal crack that opened up at the end of a minimum 7-day cold snap. Temps as low as -5 degrees Fahrenheit. The crack was approximately 1/4 inch wide, and has now closed. does it make sense that this crack could have been caused by frost heave (horizontal force), and has since closed up once the ground began to thaw?

oldestguy · Feb 9, 2018

Hey, what tells you that frost heave only goes up?? It goes to the least resistance, apparently the wall. You might want to think about digging down about foot (to be below plants, etc.) and lay a 3 ft. wide closed cell Styrofoam insulation sheet. One inch would be the least thickness. Then attach that same type insulation to the wall above that sheet. Protect the daylight part of the insulation with a Masonite sheet or similar. Otherwise sun will deteriorate it. A thick paint coat also works, but may have to be renewed now and then.

PEinc · Feb 9, 2018

I have seen this happen a number of times as you described. Usually it happens on the north side of the building and where there is not good drainage away from the building. Freezing soil pushes laterally which cracks the block wall. Snow near the wall also prevents the melting snow and roof run off from draining away from the wall.

http://www.PeirceEngineering.com

OldBldgGuy · Feb 9, 2018

It's funny how little everyone seems to understand about frost. The directions that it goes, where it comes from, and the force that it exerts. Yes, you southern types don't have to deal with it, but the people who do are woefully under-educated. Read & heed oldestguy.

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frost heave on CMU basement wall

PSUengineer1

Structural

oldestguy

Geotechnical

PEinc

Geotechnical

OldBldgGuy

Structural

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