1 A retired Regular officer who also is employed by the federal government and is subject to the dual compensation statutes may have that reduction reduced because of the waiver of retired pay to receive VA benefits.
If they don't, then 4 thick is usually standard for a patio slab, how large or small it is doesn't really matter. The most important part is the sub-base. Make sure you have a good gravel base. I would recommend at least 12 inches of compacted gravel. I like gravel where the aggregate (rocks) are no larger than 1.
Determine the joist height for the system. To get the height of the joists, subtract the thickness of the decking from the distance between the top of the slab and the bottom of the patio door threshold. In our case this was 2-1/2 inches. You will probably need a minimum of 1-1/2 inches to do this project.