Tree Fort: Treehouse Tips and Building the Adventure Bridge

In this week builds this unique freestanding Tree Fort from a kit.

The Tree Fort will include an adventure bridge that will connect to an oak tree in the backyard.

Time: 12 hours over two days.
Difficulty Rating: This project rates a 2 out of 5 on the Weekend Handyman difficulty scale.

Materials:

Tree Fort kit
Safety glasses
Gloves
10' step ladder
Hammer
Heavy-duty socket set
1/2" drill with long auger bits
Impact driver
Posthole digger or power auger
Compound miter saw
Router or belt sander
Pea gravel
Fast drying cement
Short pieces of rebar
6' level
Clamps
1-5/8" deck screws
2 x 6 ledger board
4 x 6 ledger board
10" galvanized lag screws
Rope rail
advertisement

Figure A

Figure B

Note: For this particular project the trees in the homeowner's backyard were too tall for their children. To combine the best of both tree fort and treehouse worlds, we decided to build an adventure bridge that connects the fort to a tree so the children can enjoy both!

Tips for Building a Treehouse

Look for groups of trees (figure A) that are together for good, solid structural support. You won't have to build out with artificial supports.

Use only big trees that won't sway as much when the wind blows. All trees sway but the bigger the tree the less the movement, which means more support.

If you're working out in the woods this means you'll probably be working on uneven ground, so you'll want to find as flat an area as possible for the ladder.

Be sure to tie the ladder at the top to a branch or branches with a rope.

It's a good idea to tie your saw to a belt loop to prevent having to go back down to the ground if the saw slips out of your hands.

Create a pulley system (figure B) for hauling lumber up from the ground.

The lumber doesn't have to be new -- scrap wood works fine.

When building a treehouse it's a good idea to have a professional inspect the tree for dead branches, and then you may want an arborist to come out and prune those branches for you.

Figure C

Figure D

Figure E

Figure F

Figure G

Building the Adventure Bridge

Attach 2 x 6 ledger board to corner posts (figure C) 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 (figure D).

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 (figure E). Pre-drill holes in the tree. Attach the board to the tree using 10" galvanized lag screws.

Don't fasten the main bridge supports directly to the tree, instead, perch them over a support (figure F). This will prevent the entire structure from moving when the wind blows. Also, it will allow room for the tree to grow.

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 (figure G). Attach planks to bridge spans.

Secure the ladder to the bridge with lag screws.

Attach rope rail from the tree fort to the tree for extra security.