How much concrete

[64auto]

I have a contractor building my garage. He said the footer will have 8" of concrete. Is this enough? The garage will be 2 stories

 

[twostory]

For my two story garage, I used 24 inch wide, by 12 inch thick footers. #3500 psi concrete, with three (3) #5 rebar the entire length.

You can ask your local building permit people this quesiton, my county had a 2 page instruction sheet on footers that they gave me.

 

[rotus7]

That sounds a little on the small side to me, however, you do consider the soil bearing capacity when sizing footers. If you're on bedrock or your soil is very dense and stable clay, you don't need as large a footer. Where are you located?

 

[V-10 Killer]

I believe the rule is: as deep as your block/wall width, and twice as wide. I just put 8x16" foundations, but I'm only doing a single story garage. But I believe when we built my dads 2 story house, 8" deep was what we used.

 

[PAToyota]

V-10 has the rule of thumb, but Rotus has the right answer. Most cases the rule of thumb will serve you well, but always best to check the bearing capacity of the soil and design accordingly.

 

[brownbagg]

code is 12 inches

 

[V-10 Killer]

V-10 has the rule of thumb, but Rotus has the right answer. Most cases the rule of thumb will serve you well, but always best to check the bearing capacity of the soil and design accordingly.

I agree completely. Always check with local authorities first.
I strictly meant as a rule of thumb.

 

[PAToyota]

code is 12 inches

What code? Where?

 

[pwright]

Where would one find the bearing capacity information? Are samples required from the exact building site, or will a city have data on typical soil bearing capacities in specific areas?

Thanks.

 

[PAToyota]

For a larger project, you would definitely take samples from the actual site - likely several spaced out across the area being built upon. You may be able to get a civil engineer to give you a worst case scenario for your area and then build to that.

 

[john56h]

8" thick by 16" wide footings are very typical for residential dwelling units and residential garages around here...in Southern New York State. A few municipalities have required 10" thick by 20" wide, but they are far and few between and I think they are mainly concerned with many of the larger homes that are actually "almost" three stories.