I am planning to have a concrete floor poured in my existing 25' x 24' pole barn. Barn is about 30 years old so it doesn't have any settling occurring. Contractor plans to pour 5 inches of 4,000 PSI concrete with rebar reinforcement on top of a compacted gravel base. The current dirt floor will need to be dug down 8 - 10 inches, and then 3-5 inches of gravel brought in and compacted and then 5 inches of concrete on top of that. I have some questions/concerns that I wanted to get some feedback on. I attached a few pictures for reference. 1. Should a vapor barrier be put down between the gravel and concrete? Contractor didnt mention about doing this so I want to ask. 2. I believe that to bring the floor to the correct height so my garage doors still close properly the concrete will come up a few inches along the perimeter skirt boards (which effectively will also be used as forms I believe). Should I brace the outside of the boards to prevent the boards from bowing out when the concrete is being poured? 3. Do I need to be concerned about concrete being poured under the skirting boards and then any heaving during the winter months (I live in upstate NY) causing the boards to heave upwards? Would the compacted gravel underneath prevent the concrete from migrating under the boards? 4. Along the posts that protrude into the inside, should I apply any type of expansion strips (felt/tar paper) along the bottom where the concrete contacts the post, to allow for movement of the concrete? Thanks very much for your feedback!