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Frost Depths

Frost Depths

Frost Depths

Wisconsin Enrolled Commercial Building Code and BOCA both, similarly state "...foundation walls, piers and other permanent supports of buildings and structures ...shall extend below the frost line of the locality.

As a general rule in my area of Wisconsin, we assume frost levels to be 40-48" below grade.  This, however, has only been, to my knowledge, a well-accepted common assumption.

I need to determine the frost depth in Philips, Wisconsin, which is further north from my area.

Does anyone have or know of a handy map, chart or useful reference showing frost depths per locality?

Thank you!

RE: Frost Depths


Thank you for your effort, but I cannot get the link to work!  Any other suggestions or comments?

RE: Frost Depths

I've used 48" depth in that area for more than 30 years.  You could call any one of the Dept of Comm. S&Bldg. divisions and they'll clue you in.

RE: Frost Depths

If you find one let me know, I am still looking. See my question Thread256-74708. With all those answers I still can not find a map showing the actual frost depth for specific locations.

RE: Frost Depths

See http://folio.legis.state.wi.us/cgi-bin/om_isapi.dll?cli...

You need to click on 82.30, scroll down, click 'More' about 4 times until you reach Comm 82.30(11)(c)2.d. Then load a 56 page pdf file.
Map of frost zones is Figure 82.30-1 (on page 12 of file);
Table of frost depths per type of (backfilled) soil & frost zone is Table 82.30-6 on following page.

Results: Phillips is in Price County --> Zone C.
Predicted Depth per Soil type in Zone C:
Clay & clay loam 3.5 feet, Silt loam & silty clay loam 4.5, Sandy clay loam 5.5, Sandy loam & loamy sand 6.0, Sand 6.5, gravelly sand 9.0 feet.
This was in the Plumbing Section re minimum burial depths.

You can search Wisconsin statutes from http://folio.legis.state.wi.us/

I also found references to the following document which may be of interest:
U.S. Army (1985) Pavement design for seasonal frost conditions. U.S. Army Technical Manual TM 5-818-2.

RE: Frost Depths

Call the building inspector, he should know what is required and is going to issue a construction permit at some point and you might as well get to know him.

RE: Frost Depths


I have contacted Wis Comm Dept.  The plan reviewer I spoke with told me frost depth is no longer considered as part of the Wis plan review.


Check out (kenvlach) for Wis, and (PEinc) for extreme depths.  Both helpful.


Thank you, very much, for your time and effort.


Thank you, very much, for your time and effort.  The values on the map are definitely extreme.


I will contact the local inspector.  Thank you!

To all:

Dependant upon the significance of the project, I recommend hiring a soils engineer to obtain all pertinent information necessary for designing an adequate foundation.  I will be receiving a soil report for my project in a few weeks.  I just wanted some early insight for various reasons.  

Thank you all for your time, effort and support!

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