Chapter 4 Foundation ?

[tbz]

1st off, Chapter 4 is not my strong point of knowledge, so though this might seem like an odd question, for the life of me I can't find the correct section to apply to a design.

Current PA IRC (2018):

The back of the home is being built with part of the basement level as a walkout with retaining walls. flanking out from the sliding door and double window.

Back of the home is 44ft wide and the walkout area is about 16 foot wide +/- a foot or two, almost centered.

• Frost depth requires 48" deep footings
• So at the walkout 48" deep min footings
• Backfill will be starting at 42" high on each side of the walkout area extending out about 16 feet to grade

Here is my question, I am looking for the code section how far does the fill need to extend away from the home keeping the foundation that is not part of the walkout at or below the 48" min depth. The footing is a stepped down footing for the walkout area and I am trying to find the section that sets, the distance each of the setback needs to be from the face of the retaining walls for the walkout, for each side for where the stepped up foundation is for the rest of the home at a higher level.

I have always thought 10ft because of the sloping surface water drainage requirement of 10% for 10ft min.

But that can't be it, R403.1.5 is for the slope of the footing telling you to step it.

R404 seems only to cover the retaining wall portion and not the step footing behind it for the home.

Thank you in advance for the help finding this min distance and section number.

 

[TheCommish]

a minimum of 48 inches of cover in all directions, frost goes sideways

 

[steveray]

I'd agree with the commish

 

[mtlogcabin]

Check the tables for other options

FIGURE R403.3(1)
INSULATION PLACEMENT FOR FROST-PROTECTED FOOTINGS IN HEATED BUILDINGS

TABLE R403.3(1)
MINIMUM FOOTING DEPTH AND INSULATION REQUIREMENTS FOR FROST-PROTECTED FOOTINGS IN HEATED BUILDINGS a

 

[tbz]

Thanks all, so the minimum frost depth section table of the code applies in all directions.

Just seems light on the distance.

Again thanks - Tom