FOOTINGS FOR A PATIO

[karmensandiego]

Hi!
I am trying to put together a proposal for a customer and need some help. My friend has a home improvement company but he hasn't done much work with footings before, so he asked me to find out the answers to a couple of questions and then I had a couple of my own!

how deep is a footing for a patio supposed to be?
(this is my question - I don't have the dimensions of the patio with me
but if you can give me an example of an average patio, that will help.)

how much concrete is needed for the footings?

we live in Pa. and I need to know what to charge a customer for putting in a patio!!!
PLEASE HELP ME.

[Rich]

Patio footings are debatable for depth. The main reason anything has a footing is to spread the load of it to the surrounding dirt. The reason for the deeper footings is for frost. Typically a patio will have very little weight on it compared to the structure itself and usually don't have a lot of frost problems. In MT / CO a typical footing is 36-48" deep yet you will see patio footings set at 12" or right on the surface with a 16x16 concrete pad.

Now for my opinion.... I would put them in at least 2' down. Then there are 2 options.
1. A concrete pad with some gravel under it and use a 4x4 p.t. post.
2. Use a 8" sonotube filled with concrete to a couple inches above ground then put the post base and a 4x4 p.t. post up to the structure.

To figure the concrete amount you can try out my calculator for cylinders located here. (http://www.construction-resource.com/circular_slab.php)[/url]