Bigfoot Systems® bills itself as North America’s Original #1 Selling Pier Footing Form, which I would say is most likely 100% or more correct.
So, what exactly is a Bigfoot and why would one use one?
Before we get carried away, I have never used a Bigfoot and this is not a celebrity endorsement. This article began with Hansen Pole Buildings’ Designer Greg Lovell asking me what I thought of the system.
Bigfoot is a footing form which is used to form a pier base under a cardboard construction tube (think Sonotubes: http://www.hansenpolebuildings.com/2013/11/sonotube/).
Unless one wants to make a significant investment in concrete filling a very large diameter tube, it is more economically practical to increase the size of the footing (maintaining a smaller diameter tube) in order to properly distribute the downward forces over an adequate surface.
In a previous article we shared why it takes a fairly large footing to spread the weight out (read more here: http://www.hansenpolebuildings.com/2012/08/hurl-yourconcrete-cookies/).
There are some limitations as to the “smallness” in diameter of the cardboard tube. In cases with concrete encasement around an embedded column, Code requires a minimum of four inches of thickness of concrete on all sides of a column. The diagonal measure across a nominal 6×6 (actual 5-1/2 inch by 5-1/2 inch) column is just under eight inches, meaning the smallest possible Sonotube would be 16 inches in diameter.
While Bigfoot comes in 20, 24, 28 and 36 inch diameters. Only the largest size will accept a tube over 12 inch diameter.
I am certain Bigfoot offers advantages for many types of construction, especially with decks. For post frame construction, in most cases it appears as if it would be added effort and expense. In order to be utilized with an embedded column, a 36 inch diameter or greater hole would have to be dug – and rarely are auger bits this large readily available.
The only true practical case I could make for the use would be if one had soil which collapsed as the hole was being dug – thereby forming a crater.