I am building a new porch onto an old house. The original porch basically was built right on the ground, given that it survived almost 100 years I can't complain but that will not fly today so we're building it according to hoyle and want to make sure it will last another 100 years. The new porch will have a brick veneer and the porch roof will support an upstairs bedroom addition so the footing is fairly robust.
The plans call for a 14" wide footing 12" deep with 3" of 3/4 minus compacted gravel under the footing. Then, there will be a second pour with a 6" wide, 2' tall stem wall on top of the footing. It's my intention to hand dig a trench 14" wide and 15" deep, put 3" of compacted gravel, and pour the footing directly into the trench with no forms, the drawings indicate the foot print of the gravel to be a good bit wider than 14" but gives no dimension. Does the compacted gravel pad have to be wider that the concrete or can I do what I said above?

 

That depends on your inspectors. After all, they are the ones that have to sign off on it.

I have never had a specification for the extra width of gravel under a footer. As long as I had the depth of stone called for it was approved. I just dig the trench and use the trench as the form, pour in the stone and compact.