|That dog is one hell of a supervisor.|
A couple weekends ago, the kids and I built a treehouse. I guess "house" is an exaggeration: no walls, no roof, and not much room. But, it is attached to a tree, and you do have to climb a ladder to get there.
|Some people think vice is not a good foundation, but occasionally it works out. (That black thing in back is the bumper-seat, not haging beneath the structure.)|
The treehouse begins with the tree. In this case, no dendritic cradle, and not even any useful branches, just a slightly off vertical pillar of conifer. For that reason, and because I rent this place and may be required to tear it down someday,* my idea was to use 2" x 8" boards more or less like a vice. Four threaded steel rods, bolted tightly together clamp the boards to the tree (a couple of nails held them in place during drilling and tightening, but would not be enough to support weight by themselves). The result is that the treehouse is minimally bothersome to the tree; as it grows, the bark below will swell a bit, increasing the support. The bolts could be loosened if it looks like the tree is getting squeezed too much, but I doubt that will happen.
Architecturally, I think treehouses should be vernacular and adaptive, expressions of the tree and the inhabitants, and not a static imposed design. So the basic cantilevered vice idea, which may have supported the kids, but not me, required some changing, and we added posts to the outer end of the beams. The joists, rather than being parallel and evenly spaces, radiate slightly to accomodate the geometry of our platform, and the sheet of plywood for the floor has a cutout that hugs the tree.
Those posts express another aspect that I've always thought crucial to a genuine treehouse:they are salvaged. Each consists of a couple of 2 x 4's that used to be a neighbor's bathroom wall, nailed together and cut to fit the odd lengths between beam and the rocks I dragged into place. Ascent is by means of half a step ladder whose braces and other half were getting rickety, and wwas removed; it is lashed into place with some rope salvaged from a boat headed to a landfill.
|Almost done. The skinny post was a temporary support, and the real ladder is not in place, but you get the idea.|
The treehouse will continue to evolve, and the kids will accesorize it. Already, we added a seat beneath, consisting of a big floating boat bumper suspended from more of that rope. The space beneath the floor, I should mention, was designed so I can stand up under it, out of the rain. The campfire ring nearby may need to scoot over a few feet for safety's sake, but will remain along with the sod-sofa that has been in place ever since I dug the last garden bed. Together, they are becoming a nice little outdoor living space.