Footing depth and height question

How deep do your concrete footings half to be in relation to how tall your sonotube is?

Comments for Footing depth and height question

Average Rating starstarstarstar

Click here to add your own comments

Aug 26, 2011
Rule of Thumb
by: Editor - Rich Bergman

The real issue is not height of sonotube to the depth of the footing but the depth of the footing in relation to the width of the sonotube.

Force from a pier is directed downward and at the bottom of the pier the force is then dissipated straight downwards through the footing as well as at a 45 degree angle downwards and outwards from the outside walls of the sontube.

So, the rule of thumb is: Make sure the footing does not extend outwards from the pier or sonotube more than the depth of the footing.

Otherwise, the angled downward force can break off the part of the footing that extends beyond this 45 degree force line.

So if the footing is 8" deep, it should not extend more than 8" beyond the outside wall of the pier.

Tough to explain in words but simple with diagrams.

Click here to add your own comments

Join in and write your own page! It's easy to do. How? Simply click here to return to Framing and Decking Forum.

© 2004-2022 All Rights Reserved.