ADAguy
REGISTERED
They may blow out when poured
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Pouring footers in forms.
- Thread starter Carlos711
- Start date
redeyedfly
REGISTERED
It's a minimum. You don't have to be an engineer to figure this out.
Inspector Gift
SAWHORSE
SIDE NOTE: We require the concrete to be consolidated within forms or constrained within undisturbed, earth trenches, to maintain compressive strength, as per ACI 318.
bill1952
SAWHORSE
So explain please if only a minimum 12" x 8" plain footing is required, with an 8" wall atop it, why would a footing 8" thick but wider than 24" be a building safety problem? I understand it may be no benefit but am not seeing the detriment.
mtlogcabin
SAWHORSE
R403.1.1 Minimum size.
The minimum width, W, and thickness, T, for concrete footings shall be in accordance with Tables R403.1(1) through R403.1(3) and Figure R403.1(1) or R403.1.3, as applicable. The footing width shall be based on the load-bearing value of the soil in accordance with Table R401.4.1. Footing projections, P, shall be not less than 2 inches (51 mm) and shall not exceed the thickness of the footing. Footing thickness and projection for fireplaces shall be in accordance with Section R1001.2. The size of footings supporting piers and columns shall be based on the tributary load and allowable soil pressure in accordance with Table R401.4.1. Footings for wood foundations shall be in accordance with the details set forth in Section R403.2, and Figures R403.1(2) and R403.1(3). Footings for precast foundations shall be in accordance with the details set forth in Section R403.4, Table R403.4, and Figures R403.4(1) and R403.4(2).
The minimum width, W, and thickness, T, for concrete footings shall be in accordance with Tables R403.1(1) through R403.1(3) and Figure R403.1(1) or R403.1.3, as applicable. The footing width shall be based on the load-bearing value of the soil in accordance with Table R401.4.1. Footing projections, P, shall be not less than 2 inches (51 mm) and shall not exceed the thickness of the footing. Footing thickness and projection for fireplaces shall be in accordance with Section R1001.2. The size of footings supporting piers and columns shall be based on the tributary load and allowable soil pressure in accordance with Table R401.4.1. Footings for wood foundations shall be in accordance with the details set forth in Section R403.2, and Figures R403.1(2) and R403.1(3). Footings for precast foundations shall be in accordance with the details set forth in Section R403.4, Table R403.4, and Figures R403.4(1) and R403.4(2).
bill1952
SAWHORSE
From: https://www.forconstructionpros.com...cceptable-tolerances-for-residential-footings
"It is therefore acceptable for an IRC-prescribed minimum concrete footing of 12 in. (w) x 6 in. (t) with projections of 2 in. to be allowed tolerance to a width range of 11.5 to 15 in. with a minimum projection of 1.5 in. The IRC also states that the projection cannot be greater than the footing thickness, in which case a plan tolerance here would permit the maximum project ion of 6 in. to be as great as 9 in. without being reinforced (seismic zones A, B and C only)."
"It is therefore acceptable for an IRC-prescribed minimum concrete footing of 12 in. (w) x 6 in. (t) with projections of 2 in. to be allowed tolerance to a width range of 11.5 to 15 in. with a minimum projection of 1.5 in. The IRC also states that the projection cannot be greater than the footing thickness, in which case a plan tolerance here would permit the maximum project ion of 6 in. to be as great as 9 in. without being reinforced (seismic zones A, B and C only)."
bill1952
SAWHORSE
And finally an engineer's explanation of why the footing projection should not exceed footing depth if it is not (transversely) reinforced.
pro.homeadvisor.com