How to Build a Tree Fort
Building a tree fort from a kit is much less expensive and easier than building one from scratch.
Attach 2 x 6 ledger boards to the corner posts of the tree fort.
Use 2 x 4 blocks to flush the board with the angle brace. Use clamps to hold it temporarily in place. Use a heavy-duty 1/2" hammer drill with a long auger bit to drill the holes.
To attach the 4 x 6 ledger board to tree , first make sure it will be level. Stretch the board from the tree fort to the tree, level the board and make a mark with a hammer and prybar on the tree where the top of the ledger board needs to go. Pre-drill holes in the tree. Attach the board to the tree using 10" galvanized lag screws.
Lift the 4 x 6 bridge spans into place, and sue a router or belt sander to smooth any rough edges on the lumber.
Secure the beams to the tree fort with carriage bolts.
Rough cut the planks to go across the bridge. Leave the planks uneven for the classic "treehouse" look. Attach planks to bridge spans.
Secure the ladder to the bridge with lag screws. Attach the rope rail from the tree fort to the tree for extra security.