We lay a 2' x 6' on the ground next to the trunk beneath the two limbs that spread into a V. The boughs rising through the floor will become, on one side, a natural railing and on the other, a living stool. We decide, in consultation with Mr. House, on a 5' x 6' rectangle. That leaves about 14' above ground--11' to the tree house floor plus 3' extra to become the corner posts for a railing.
FOUR CORNERS
1. Fasten a 2' x 6' to the tree with two 6" lag screws.
2. Drop a plumb line from each end; mark where it falls with sticks.
3. Using a square, measure the length of your floor from each stick and mark those spots.
4. Use a posthole digger to dig two 2 1/2' deep holes. Pour 6 inches of concrete into each hole; let set 24 hours.
5. Place 4' x 4' posts in holes; pack with dirt.
6. For the frame, complete the rectangle by nailing the three 2' x 6' boards to the ends of the original 2' x 6', and to the outsides of the 4' x 4' posts.
TIPS:
• Try to rent a gas-powered posthole digger (instead of using a handheld one) to ready a hole for the cement.• The fewer screws you use when building your treehouse, the less injury to the tree.
