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Foundation Wall Thickness

Dan_Cabral's picture

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I have read that the minimum thickness of a poured concrete foundation wall for a two-story home is eight inches. When the foundation must support brick siding a ledge must be poured. Must this ledge be in addition to the eight inch width, or may it be included in it? If the latter, you end up with only a four inch wall under the sill plate to support the load of that wall, and other four inches of the wall is stepped down and forms a ledge for the siding.

Does this meet code in most places? Is it common practice?
Location: northern Virginia.

Thanks,
Dan

(post #157908, reply #1 of 8)

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Dan- I think the brick ledge would be in addition to the 8" thickness called for in your foundation wall. The whole point of the 8" is that is bearing down to your footing. The brick ledge carries the brick but not the roof and wall load. I'm not an engineer...check with the inspector to make sure.

(post #157908, reply #2 of 8)

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Dan,

Here in the Chicago area, some towns
require 8" for frame, 10" for brick
and frame. Some require 10" minimum
regardless.

Hope this helps,
Mike Merisko

(post #157908, reply #3 of 8)

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Look in your code book or call your inspection department.

(post #157908, reply #4 of 8)

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Matt,
If that is the case, when would you use an 8" "L" Block?

(post #157908, reply #5 of 8)

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Really is an engineering question with variables of dead load, soil and hydraulic load, soil structure, etc. Perfectly done, a six inch wall with extended lip can do the job but when is the last time you saw a perfect concrete pour and perfect curing weather?

(post #157908, reply #6 of 8)

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Poundcake- I don't know what an 8" "L" block is...is it a preformed brick ledge type of deal? It doesn't seem to me that you would need your entire wall thickness to be what your ledge thickness is. Maybe if there is a lot of brick going on there?

(post #157908, reply #7 of 8)

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Dan,

Here they have strict building codes and allow
a two story giving up 4" of its 8" thick concrete wall for a brick ledge.

So yes it is common here as well as a lot of other places ( been discussed here before).

The prefered way is a 10" wall with a 4" brick ledge formed out of that, but that would cost more , so very few of my clients will pay the extra $.

DJ

(post #157908, reply #8 of 8)

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I have read that the minimum thickness of a poured concrete foundation wall for a two-story home is eight inches. When the foundation must support brick siding a ledge must be poured. Must this ledge be in addition to the eight inch width, or may it be included in it? If the latter, you end up with only a four inch wall under the sill plate to support the load of that wall, and other four inches of the wall is stepped down and forms a ledge for the siding.

Does this meet code in most places? Is it common practice?
Location: northern Virginia.

Thanks,
Dan