The frost depth varies by region ... If the footing does not extend below the frost line, the footing will heave as the ...

The bottom of a garden wall footing must be below the winter frost line to avoid displacement by frost heave (refer to the frost depth map in Figure 6-3 or consult your local building department). In ...

"In some parts of the country, the frost depth can be eight feet, and footings need to extend below that level to resist frost heave," explains Bob Brown, a certified Foundation Repair Specialist ...