The Circular Treehouse – Beam Install


The first step was to install the top brackets. Well, first had to get the proper bolts. I wanted to use 3/4″ thick (radius) by 8″ long lag bolts — galvanized to support the weather. When I built my first treehouse, I just bought them from OSH or San Lorenzo Lumber. Now a days, we have Home Depot, and still OSH. Home depot doesn’t really carry large lag bolts, and OSH has a wider selection, but no 3/4″ lag bolts. Both places have coarse thread 3/4″ ungalvanized bolts, and that was my only real option. I could order something from the internet…but I wasn’t that patient. I did some test holes in a sample tree and discovered that the coarse thread 3/4″ bolts thread quite nicely into a 5/8″ pilot hole. The only problem is that they will eventually rust, since they aren’t galvanized. I figure it will be an experiment to see how long before they rust and cause the treehouse to fall down. I think it will last at least 10 years, probably 20 and maybe 30. The bolts will be “somewhat” protected from the elements, so they shouldn’t rust all that fast. I realize I’m making a mistake by not using the proper hardware, but that’s okay by me.

So, I sunk the first bracket into the tree; all was fine. I drilled the hole for the second and realized that an 8″ lag bolt is too big for a tree that has a radius slightly less than 8″ (oh, duh!). I really need to have used a larger tree, but this is the one I wanted it in. So, I traded in my 8″ bolts for 5″ bolts. They seem to get as much holding power as the longer ones, and I think 8″ is overkill.

Rock climbers use much smaller bolts — but then again, those bolts are drilled into solid granite. So, a second experiment is to see how well these shorter ones work. Before I got the shorter ones, I used a few of the 8″ ones but made a 1″ space out off 3/4 inner diameter by 1″ outer diameter steel pipe I had from moving my mill.

Here’s some more iPhone pictures:




Each beam was carefully leveled with the previous beam and then leveled radially. Unfortunately…I now realize that didn’t work so well, as some of the old beams are slightly warped. I should have ripped (or jointed) a side perfectly flat before using them…but then again…”oh well”..

More soon…

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Nathan Hoover

Wow, this looks AWESOME!!!


Considering the tree looks like to be a Sequoia Sempervirens, growth could be an issue.


stephane — I don’t think growth will be an issue; I’ve literally grown up around coastal redwoods, and they grow quite slow. They also grow around things; i’ve seen some strange things embedded in them.



It depends on the definition of slow and the life expectancy of the house. I was thinking about the 10,20,30 years numbers. It’s difficult to say from a photo, but the radius of the tree could have been multiplied by 1.5 at least in the 10-20 years period. The growth of a sequoia can be 1 meter (height) per year from what I’ve read.


Greetings Corbin~
I have been looking for a treehouse to rent and surprise my husband with for our anniversary…do you have any suggestions? I am also a Tissu aerialist and saw your lovely photos!


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