Well, a few weeks ago it finally happened. My treehouse fell down! Well, not entirely; about 3/4 of the floor fell out.
I took a few pictures with my iPhone; I’ll probably be going back in a week or so to do more cleanup and scavenging.
Here’s a view from the ground, looking up at the treehouse. The sink is literally hanging by a thread (the pipes!):
A view from inside the treehouse:
Another view from underneath:
The floor fell down and rotated on top of the things in the treehouse:
So, what happened?
Well, a few weeks ago we got a lot of rain and wind; that was probably the pushing factor that made it fall out. But, the main reason it failed is due to a bad design. I knew the treehouse wouldn’t last forever, and I knew that I did some things wrong when I built it. In the end, it lasted for 9-10 years; I started building it when I was 20, and moved in when I was 21. In a few short months (April 13th) I’ll be 31. The design was flawed in several ways:
1. HUGE 24′ spans with doubled up 2×6’s (not quite as strong as a 4″x6″), with ZERO 45 degree supports underneath the house. I initially had put a few 45 degree supports, but my lackluster attachment made them not do much, and they eventually just fell down. Now, douglas fir isn’t made to span that huge of a distance, and was prone to have a huge amount of support weight on the edges.
2. Non-floating foundation. Ideally, I should have made metal brackets that would allow one end of the attachment to the tree to “float”. Since I didn’t do that, the movement of the trees was slowly pulling the house apart. It was particularly worse when it was really windy out, and it made the whole house creak really bad. NOTE to self now that I can weld: make brackets!
3. Built-in foundation. Instead of having some joists that the real floor would be built upon, I just built it directly into the joists. That works for smaller houses, but for larger treehouses it wasn’t a good idea. The floor acted like a torsion box, and probably flexed the worse at the ends.
4. Related to #2 — “tree on wood contact”. The edges of the 2x6s had two 6-8″ lag bolts bolted into the tree. The wood-on-bark contact never would really dry out, allowing it to rot slightly.
In addition to all those problems, the other kicker was that we recently stored a bunch of stuff in the treehouse, since we rent out the “big house” on the property and needed a place to store things. Unfortunately, most of that stuff got damaged when it took a 40′ fall and had the floor fall on top of the stuff to boot.
Oh well…lessons learned!