[LIforrelaxin]

The only way to know for sure, what the two CEO is going to require is to speak directly to them. By the way this is what they are there for, it is their job, to not only make sure the rules are followed, but to also make available the information need, to properly plan a project.

Over the years requirements have changed tremendously regarding decks. I remember being told that are deck was built almost to rugged, and that we over engineered it. By today's standards it is not beefy enough.

The bottom line is post specification, my have lots of variables, such has how many posts are being used, over what span. etc. In the deck shown by GNC I have no doubt that 6x6 post where required. That is a fairly decent span for only 3 Posts. And then you look at the bulk of the landing being suported by a single post. Looking at the span if only 4X4 where used I would have suggested at least 4 and maybe 5 posts.

In the end you are likely to be better off just going with the 6x6 posts, they will provide stability, and for a small cost difference take the question out of the equation.

It is likely the 4x4 and 6x6 are both allowed, what you have to show is the engineering wise the structure can support an X lbs. load per square foot of surface area. The question is do you want to do the engineering work to show that your design with 4x4 will support the needed load, or just use 6x6 instead, and not have the question raised.