Treehouse

Instructions:

1. Find the perfect tree. There are definite advantages in using more than one tree for your treehouse - the treehouse can be bigger, and you have to use less bracing.

2.Pick your design. The picture below is a good techinique but it can change depending on the tree. 

3. Make sure you have all the equiment mentioned above.

4. The bare minimum of tools: hammer, saw, level, square, tape measure, adjustable wrench, cordless drill, jigsaw. A ladder is important, but you can get by with a rope ladder.

5. Mount the main supports. Get a strip of light wood and nail one end to one of your trees at a height about 1 ft lower than you want the floor of your treehouse. Get it perfectly horizontal with the help of a level and nail the other end to the other tree. 

6. Drill 5/8" holes straight into the tree just above the strip of wood. Do the same on the other side of the trees, this time taking the extra precaution of first ensuring the new strip is not only horizontal but also level with the strip on the other side of the tree. 

7. Now, take down the strips and measure the exact distance between the holes. Subtract this distance from 6' (not 8', unless you don't want the entrance platform), halve the remainder, and make a mark this distance away from one end of your 2×8. 

8. Drill a 3/4" hole in the middle of the board. Make another mark using the between-the-holes measurement . 

9. Now drill two 3/4" holes, each 1-2" either side of your mark and both in the middle of the board. 

10. Get a jigsaw and make two cuts between the holes to make a 2-4" long slot. 

11. Repeat for the other side of the tree. The slot allows the trees to move without tearing your treehouse apart - the more your trees move, the longer the slot ought to be.

12. Lay out platform. Leave a small gap between boards for drainage. Cut two of your 2×6 boards the same length as the decking, and the other four to the width of your decking less the thickness of two of the 2×6's.

13. Build the platform. Using 3" deck screws, attach the four 2×6's perpendicularly to one of the other 2×6's. Make sure they're spaced so that when you put it up in the tree, the perpendicular joists will miss the tree! With someone's help, put the contraption up in the tree, center it, and tie it down. Screw the other 2×6 to the other end of the platform, and check that it is centered and square. For squareness, measure the diagonals and ensure they are the same.

14. Attach supports.

15. Brace platform. As it is, the platform will wobble dangerously. Add diagonal bracing made of 2×4, and use a single long lag screw to attach both of these to the tree.

16. Lay the deck. Get up on your platform and screw down the deck. The only tricky thing here is cutting around the trunks. Use sheets of newspaper to make templates so you can cut out the holes reasonably accurately. Be sure to leave space for tree growth and movement.

17. Add a entrance way. Make it however you want. It can be a trapdoor or just a platform. Do whatever you want depending on your preference and tree.

18. Railing. Nail to the base.

19. Ladder. You can build one using wood or just buy a rope ladder.

20. Make the roof. A good way to protect against the weather is by putting a tarp up on it.