How to build a treehouse

Step 2 Get your materials

For this treehouse, I bought:

2 x 10' lengths of 2 x 10 pressure treated (PT) lumber.
6 x 12' lengths of 1 x 6 PT decking material.
6 x 8' lengths of 2 x 6 PT lumber.
3 x 10' lengths of 2 x 4 PT lumber.
4 x 6" long, 1/2" diameter galvanized lag screws and washers
1 x 8" long, 1/2" diameter galvanized lag screw and washer
8 galvanized joist hangers
8 galvanized rafter ties
Nails, deck screws, pulley for 1/4" rope
Camouflage tarp

All this cost about $250 from the nearby Home Depot. The rest of the materials came from a neighbour's old fence: plentiful amounts of cedar boards and 2 x 4 lumber. It was used for the sides, so you can just substitute whatever you'd like to make a railing/walls.

The photo is of my plan, which was sketched on a cereal box. I read around a lot first, of course: I found David Stiles' books especially easy to follow. The design changed as I was building it - I didn't end up adding the braces drawn in the bottom left elevation, and I built an entranceway platform that I hadn't originally planned.