R507.3.1

Section R507.3.1 is titled 'Minimum size' and covers the requirements for deck foundation size. A cross-reference to a table which lists footing sizes based on several variables is established. The purpose of this section is to prevent structural failure.

The model shows the framing of a deck, footings, and a footing tributary area overlay. The overlay and footings are color coordinated. The posts are spaced 150" o.c. in the long dimension, and 96" o.c. in the short dimension. Presuming a live load of 40psf and a soil load bearing value of 1500psf were used for the design, and that each tributary area was rounded up to the next listed value in the table (i.e., no interpolation was done), what is the diameter of each footing?