Cob: frost free shallow foundation

[Shannon C. Dealy]

On Fri, 4 Jan 2002, Howard wrote:

> So what you need is a foundation that goes down 4 feet or so to get below the frost
> line.  Typically a rigid foundation stem wall is built on a concrete footing below
> the frost line, "4 feet or so."  Wright used "structural fill," sharp gravel, under
> his footing to drain any water away that might freeze and heave the foundation.  If
> you take this structural fill down, the width of the footing, below the frost line
> you have structure, you have a foundation that will not heave in the freeze/ thaw.
> You also have a foundation that will fare better in an earthquake.

This is also known as a "rubble trench foundation", and if you plug this
phrase into a Google search, you will find a fair number of references
online.

Shannon C. Dealy      |               DeaTech Research Inc.
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