Once the joists and posts are secured, install the treehouse floor by screwing 2x pressure-treated lumber across the joists. I used alternating 2 x 4s and 2 x 6s to create an interesting look.

The Finger Lakes. While many tree house kits require two trees, the Finger Lakes Rectangular Treehouse plan only needs one. It does require special equipment, but the result is a 163.5-square-foot ...

It’s always good to plan before you build anything. For a treehouse, find out whether it’s covered under your home insurance. (iStock) ...