Treehouse build, feedback & expert advice

[TBrown99]

Is this a good place to seek feedback / advice on a treehouse build?

We have guidance from a very experienced tree anchor bolt maker-seller and he has approved our basic plan.

We understand the build process as having three stages:

Foundation
Platform
Enclosure build

We are going very slowly with stage one but are about to pick up speed. We aim to complete the foundation and platform this Winter.

Our tree format is: Hemlock. Two in front, two in middle, one at the back.

We have platform TABs in the two front trees and a yoke style TAB configuration in the back tree. We will install our supplementary platform TABs in the middle two trees once we get our structural beams placed. Before we do this, we need to install our yoke structure on the back tree.

We went with the hardware maker's recommendation of i-beams as the best possible foundational structure. Our main beams running parallel front to back will run 30' feet and placed about 15' apart.

Our main focus now besides the yoke, which will also be in metal, as one of us has advanced welding skills as well as onsite capacity, is the floor joists.

This is located in a hemlock grove where we could harvest timbers. We have a LT-35 Woodmizer that can access the site. So, we can make 20' floor joists, as the max length capacity of saw without extensions.... It is possible as well to move the sawmill to a nearby location with eastern white pine logs available... I expect that as far as building materials go, the white pine is less potentially problematic.... though I'm not sure. Beyond the 20' stock, is 10"-12" x 2" ideal or could we use a different format to better effect? Say 3x6s. Also, while our span between I-beams is 15 feet, we'd like to have a much wider platform so a large portion of the foot print will be outdoors decking, so we can enjoy inside / outside... This raises the question of how to join our 20' joists. In a addition to the joining here, we would consider as well adding minimal middle supports at the joints parallel to the i-beams.

The structure will be two levels with the main living housing on the upper level.

Thanks.   

[beenthere]

Good luck with the treehouse build. Not enough information given to offer any feedback or advice. 
Even a sketch or drawing? 

No idea what a "very experienced tree anchor bolt maker-seller" might offer to your build. 

[TBrown99]

We have a concept drawing and a tree & anchor pin layout drawings. The later is fixed and in progress while the look and feel drawing shows merely a dreamy image which the final product will only remotely resemble yet retain the four area divisions that we've decided on. We are using an emergent design approach where what we achieve in stage 1 (foundation) informs and shapes our stage 2 (platform). We know that we'll soon be on stage 3 (housing) but we'll let it percolate for now.

We need to develop our plan for the joists, as mentioned.

We purchased about $5000 worth of hardware from treehouses.com and have discussed the build with owner Michael Garnier. We also had a former employee of Vermont's Treehouse Guys spend two days with us on pin installation. He instructed my foundation builder Brendan on related issues. Both are available for consultation.

The location is about 1 mile into a hemlock grove with mixed hardwoods via a rough but highly passable forest farm road. The use will be for real living space as well as possible rentals -- with the support of nearby home for comfort needs (showers, etc.).

So, we're focused now on treehouse floor joists. Hemlock or Pine. And how to span them.