I'm building a 7 x 12 tree house platform on a single tree.

The layout is one tribeam Attached to the tree with tree house attachment bolts. Then in front of that are two 6 x 6 posts with a 4x6 beam going across. The bottom of the tribeam and top of the post beam are parallel. I’ve laid my 2 x 8 joists on top of the beam in front and attached to the tribeam with joist hangers (in retrospect would’ve made more sense to lay joists on top of tribeam but too late for that now)

Question: To allow for a tree growth/movement, should I attach the joists to both beams or just leave the joists floating over the posts.

overview of tree house construction so far

under deck view identifying joints in question

  • This question would benefit from a photo of your situation and layout. Feel free to mark up (draw with Paint if you have nothing else) to indicate missing elements or the part of the configuration you're asking about. Mar 7, 2022 at 22:52
  • See photos above. The hurricane ties are attached to the beam but not to the joists. Not sure if I should leave them floating like that to push out as tree grows or if I should fix everything down
    – Chris
    Mar 8, 2022 at 0:07
  • Several questions. How long do you expect to use the treehousde? It looks like your attaching the tree hiouse to a pine tree of sort right? They tend to grow fairly fast, compared to a hardwood tree. Assuming the tree grows and the trunk size increases, where do you think the stresses are going to be?
    – SteveSh
    Mar 8, 2022 at 0:28
  • 2
    You're a long way into construction already, but it looks to me like you're just using the tree as a single post to hold up one end of the deck. It may well have been easier to have sunk 2 more posts for the back corners and left the tree out of the equation entirely - just make a cutout for the tree at its current size and enlarge the cutout in the future as necessary.
    – FreeMan
    Mar 8, 2022 at 13:32
  • 1
    Given what you've shown, I would fasten the hurricane ties to both the joists and the beam at the far end, and let the joist float to some extent on the beam that's attached to the tree. That's essentially what I did with the tree house I built (see earlier comment).
    – SteveSh
    Mar 8, 2022 at 15:21

1 Answer 1


Manufacturer of the treehouse attachment bolt system says no need to keep anything floating on a one tree/two post treehouse.

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