Water Level

Today I decided to mark the trees where the main beam will go. I immediately ran into a problem: how to place a level mark on the two trees? The laser level and the regular level along with a string both depend on a bubble, which isn't very accurate across a twelve foot gap. Also, neither of those methods can set a level mark on both sides of a tree.

After a good amount of trying to make it work, I remembered how to make a "water level". This is so simple it borders on genius.

Materials:
- pick up a 25 foot length of clear tubing
- you'll also need a bucket

Steps:
- dunk the hose in a bucket and remove the air
- being careful not to let any water out of the hose, carry the hose up the ladder (you could carry the hose in the bucket)
- hammer a small nail through the hose at the height of the mark
- with your thumb over the other end of the hose, climb down the ladder and up to the other mark
- get close to the same height, and release your thumb from the hose
- watching the first side of the hose, adjust the height of the second side until the water intersects the nail

Congratulations, you've just made a highly accurate level!

Braces

So I've come up with several variations on braces. The issue is that the brace must be strong enough to support a heavy load, but also allow the frame to float (and potentially lift and slide).

• The first version was a simple triangular brace -- well, not that simple. Click for a close-up. My plan was that by using two 2x6s the support would be stronger. I think this would be a very good support for a stationary single-tree house. However, the potential push-and-pull created by the other tree swaying could lead to the brace being bent off of the tree.

---

• The next idea I had was to use some sort of steel channel as a guide. This would take care of the sliding friction, provide support, and still allow the frame to lift if needed. Unfortunately, I couldn't find anything "stock" to work with, and "custom" is not in the budget.
  

---

• In order to support the metal brackets, I added a beam. The pictures below show how this transformed to a simple brace made from 2x6s. If I can find a steel plate I'll add that to allow the frame to slide along the brace.

Plan Overview

So for the past year or so, the problem of how to design suitable support structures has been bugging me. The sketch to the right outlines the problem. The medium-sized tree is on the left, and the large tree on the right. The trees are both very high, so I need the design to handle sway in storms. Additionally, the large tree is leaning several degrees from vertical.

My idea is for the left-tree to act as a pivot for the frame, with the large tree surrounded by the deck frame. This will allow the deck to "float" if the wind lifts it, but will keep it aligned on the support braces. The large tree will support most of the weight.

Site Selection

Our yard has several medium/large black walnut trees. Unfortunately, black walnuts do not have low branches. On several of the trees the first branch is more than 20' off the ground. To make matters worse, few of the trees are well situated for a tree house. 

The best we could come up with are two trees about 16' apart. That's a big span, but one of the pair is a large tree (the other is medium).

The challenge is how to design a support that will:

1. span the distance between the trees
2. be flexible enough to deal with potential wind problems (lift on the platform/tree house; sway in the trees
3. be strong enough to support the tree house

Start

O.K. So for a couple of years we've talked about building a tree house in our backyard. We've looked at pictures in books and on the web, we've drawn up some sketches, and we've even selected the trees. Unfortunately, limited time (and money) have kept the project from getting off the ground (see, that's a joke: treehouse, off the ground,... nevermind).

But, with a little luck this summer is going to be the one when the tree house gets built -- or at least gets started.

This blog is where we're going to record our progress.