George:
When I built my model room I lowered the ceiling 15 inches. Now I have the whole top of my room for storage. I use a pole with a hook on it to slide the boxes in and out of the space. The space is for long term storage. All of the boxes near the outside of the space can be easily gotten to.
You can use the space overhead buy building large deep overhead shelves. As long as you can stand up in the room, the rest of the head room can be used for storage.
Also, when you build model display shelves, the lower part of the shelves is typically too low to view models. So I keep my unbuilt model kits in boxes under my model display shelves.
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