Frost line

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The terms frost line, frost depth, and freezing depth refer to the depth that the water in soil is expected to freeze. The frost depth depends on the climatic conditions of an area, the heat transfer properties of the soil and adjacent materials, and on nearby heat sources. For example, snow cover and asphalt insulate the ground and homes can heat the ground.

The term frost front refers to the varying position of the frost line during seasonal periods of freezing and thawing.

Some regions have no frost depth and some regions have several meters of frost depth. In Arctic and Antarctic locations, the freezing depth is so deep that it becomes year-round permafrost, and the term "thaw depth" is used instead.

Building codes sometimes take frost depth into account because of frost heaving which can damage buildings by moving its foundation. Foundations are normally built below the frost depth for this reason.

There are many ways to predict frost depth including n-Factors which relate air temperature to soil temperature.

[edit] Sample frost lines for various locations

• Minnesota, USA (2007):
  • Northern counties: 5 feet (1.5 m)^[1][2]
  • Southern counties: 3.5 feet (1.1 m)^[1][2]

[edit] References

1. ^ ^{a b} Minnesota Department of Labor and Industry. Frost Depth: Minnesota State Building Code Rules 1303.1600 [map], 2007 edition. Retrieved on 2008-01-30.
2. ^ ^{a b} The 2007 Minnesota State Building Code. Minnesota Department of Labor and Industry (2007-10-09). Retrieved on 2008-01-30.