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No Frost footing,403.1.4.1 2 story with walkout basement
February 17, 2020
12:25 pm
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Forum Posts: 2
Member Since:
March 23, 2016
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I have houses being built where the Engineer is stating 403/.1.4.1 and states below. I do not think this meets the intent of the code. There is no thermal protection, the footing is not 12″ min depth. Crushed limestone is for pre-cast foundations, which this is the standard Missouri poured wall & footing.  Next – i cant find where this meets ASCE 32 everything i read about asce 32 on heated building you have to protect the footing with approved foam. The Eng also didn’t inspect or document the 8″ lifts of soil or crushed stone(AB3) .\

What do you all think? Can i approve this method of crushed rock(which is questionable) installed on a lot with fill,for a 2 stoy house with a walkout basement with no 36″ frost footing which is required in this area of Missouri.

• The subgrade issues at proposed footing elevation that were observed required three feet (3.0’) of soil fill to be removed to expose undisturbed competent clay.
• The elevation of the undisturbed competent clay is over 3.0’ below final soil grade at rear walkout
• IRC 2018 R 403.4.1 allows the use of crushed stone footings for residential structures. Crushed stone does not cause frost heave when subjected to freezing temperatures.
• IRC 2018 R403.1.4.1 requires that the footing bear on soil below frost line (3.0’ below final grade)
• designed a mat foundation/footing that used compacted crushed stone (AB3) to extend the permit plan footing elevation to the competent soil below frost depth (3.0’).
• The concrete footing (per permit plan) was constructed directly on top of the compacted crushed stone mat foundation/footing (near final grade), which transfers the load directly to the competent clay below the frost depth.
• The non-expansive crushed stone footing under the concrete footing transfers the load directly to the competent clay below the frost line.
• This design meets IRC 2018 R403.4.1 and R403.1.4.1