R507.3

Section R507.3 is titled 'Footings' and covers the requirements for deck foundations. The load that the foundations must be able to carry, a cross-reference to a figure in this code which depicts different allowable foundation and post arrangements, and a cross-reference to another section of this code which covers frost protected foundations is established. The purpose of this section is to prevent structural failure. This section has an exception which allows decks to not be supported on a foundation system where it is free-standing with joists supported entirely on grade. The purpose for this exception is to clarify that such deck construction is considered to pose a low risk of hazard and is allowed.

The model shows a representation of figure R507.3 which depicts 6 different foundation and post arrangements which are allowed. Review of the figure will show that it has several notes which are not contained in any code section language. Of particular interest is the requirement for posts to be centered on or in the footing. Careful layout and construction is needed to assure that posts do not end up offset from the center of piers. Correction of such a mistake can be very costly.