How To Build A Treehouse—Basics First!

Published on | Log Homes |Leroy Walker

It’s almost hard to believe that tree houses, intended for adult occupancy, actually exist; but they do! Like any traditional home built on land, tree houses can be massive and multistoried or they can be modest, depending on how much money one is willing to spend. In Oregon, there is a tree-house that is a Bed & Breakfast resort--Vertical Horizons Tree House Paradise--that offers three state-of-the-art guest quarters.   Another Bed & Breakfast tree-house complex is located in Takilma, Oregon—Michael Garnier’s B & B--which offers its guests a selection of 13 suites to choose from! Can you imagine?

People in all parts of the world have created dream-homes in the trees--from Alaska to Hawaii to Turkey to Papua New Guinea—where fun, funky, romantic, fanciful dwellings allow life to become a lot more relaxed and where people’s perspectives of the world gain an entirely new feel!

More elaborate tree-home construction employs state of the art technology as well as construction methods that are designed to be environmentally respectful. Did you know that some tree-house designs come with plumbing, electricity, cable, heating & air-conditioning and even fireplaces!? Obviously, all the details that go into building a functioning tree house can’t be covered here, but we can go over some basic construction principles that one needs to be aware of from the get-go!   Whether you are considering a casual tree-shack or a multi-tiered fantasy abode, first and foremost---even before you speak with an expert in the field of tree-home construction---check with your local planning authorities as to whether or not there are any restrictions on tree-home construction. If the tree-home will be used as a permanent dwelling, there will most likely be rules and regulations concerning dimensions or even restrictions regarding windows that might overlook adjacent properties! And to help the process along, it never hurts to buy a magazine or two that specifically deals with tree-home construction where ideas for floor-plans and surprising amenities can inspire, motivate and excite!

But let’s go over a few of the need-to-know fundamentals:

1: The Tree Selection:

Obviously, choosing the appropriate tree will come first; and building between two trees is the easiest for large treehouses.   When three or more trees are used, it will permit increased movement in different directions, which is something you want to minimize. You’ll also need to decide if you want your tree-home to be mostly secluded or highly visible.

The tree will be your guide and you’ll want to follow the form of the tree and take into consideration any growth or movement. And the bottom line is: the house will need to accommodate the strength and configuration of the tree or trees being utilized. Choose a hard-wood tree for maximum support with load-bearing branches at least 8 inches in diameter; and seek out durable sugar-maple, oak, fir, beech, monkey-pod or hemlock trees. Definitely avoid cottonwood, spruce, birch, willow and sassafras trees if strength and longevity are what you are looking for.  Some trees don’t live for generations, so know your tree species! Also, other factors need to be taken into consideration such as the growth rate and resistance to pests; and if your tree is too young or too old, the required support will be compromised.

2: The Platform:

The platform will truly provide the foundation for the rest of the home---it’s the key component and needs to be positioned in near proximity to the trunk and enhanced with diagonal bracing for maximized strength if not support by branches or posts. You can minimize tree damage by perching beams and braces on top of specialty fasteners instead of pinning them to the tree.

And be aware that pressure-treated wood will last longer but can be embedded with toxins so be sure to wear appropriate clothing, such as gloves, and wear a respirator when hand or power-sawing.

Keeping the platform absolutely leveled and balanced centrally around the tree is crucial to minimize swaying as well as to effectively support uneven loads. If rope or wire is used to help secure the platform, keep in mind that rope or wire that is too tight can kill the tree. Choose stainless-steel or galvanized coach (lag) screws or bolts. Un-galvanized nails will eventually rust which will likely lead to disease or rotting. Also, lag-bolts cause less tree-damage than through-bolts.

For tree house with more weight, spread the weight among an adjacent tree; and be sure to put the load over the base of the tree and not on only one side. In high-wind areas, build your tree-home in the lower third of the tree.

3: The Floors:

The flooring will be added once the platform is securely in place; and exterior plywood sheet or tongue-and-groove floorboards can be used. It’s important to leave 2” spacing around any tree trunk that might come through the floor since this will allow for additional growth and movement. Obviously, you will want a level floor capable of handling the entire weight of the house.   A rigid, solid, flat floor will prevent any twisting of the structure; and a flexible design will incorporate a rigid floor unit that can slide over the beams below and allow the beams and the trees to move independently.

4: The Walls:

The home’s walls can be constructed two ways: 1) on site and actually while in the tree or 2) prefabricated on the ground and then raised-up into the correct position. Tree-homes that are larger utilize the second approach---hoisting pieces up into the tree---since it is not only less complicated but is safer!  Using power tools is easier and construction can be accomplished faster and more accurately on the ground. You’ll, also, want to design the treehouse in individually built sections that can be joined together with ease on the ground. Then the supports, floor, walls and roof can be hoisted (via a pulley system) into the tree and quickly positioned into place. Hoisting pieces up a tree may sound like a lot of work, but in Costa Rica, a 1,300 square foot tree-house was constructed by pieces of the home-to-be being zip-lined through the jungle canopy!

While on the ground, doors and windows can be added to wall pieces which will reduce in-tree construction time.

The walls need to be load-bearing and stout enough to not only support their own weight, but the weight of the roof, as well.

5: The Roof:

If at all possible, assemble the roof on the ground, but if branches are going to pass through it, constructing the roof in the tree is usually the better option. In areas of the home where trees will penetrate the roof, allow 3” gaps or spacing around the tree to cater to growth and movement. If, however, the tree will flex a fair amount in the wind, make spacing where the tree penetrates the roof to more than 3 inches. Once the rafters are built, the covering of the roof can be exterior plywood or planks that are covered with tar paper. Depending on where you live, shingles or thatch can be used as the roof’s covering. If at all possible, used recycled shingles or shakes; and be sure to insulate your roof as well as the floors and walls for comfortable living throughout the year, especially if you live in a climate with hot and cold seasons.

6: Salvaged Pieces:

Be as eco-friendly as possible and utilize as many recycled materials and waste materials as possible! Building-reclamation depots are well known for their availability of inexpensive supplies including doors, windows, ladders, stoves etc.

Good-to-Know Info:

*** Use a minimal number of fasteners. One large bolt is much better than multiple screws or nails.   This equates to fewer puncture holes, making for a healthier tree. Understanding how trees grow and respond to the special bolts that are embedded into the tree is critical to proactively minimize tree stress and damage.

*** Perch the home on top of fasteners instead of pinning beams to the tree. This permits movement and growth. Be sure not to position fasteners too closely together to prevent weakening that part of the tree; but be aware, too, that fasteners can cause infection.

*** Make the fewest punctures necessary without compromising the safety of the tree-home.

*** Avoid slinging ropes and cables over branches since they can cut through the bark.

*** Talk to your neighbors before building. If neighbors complain about such things as privacy issues, it can be a very real issue and thwart your plans!

*** Speak with your home-insurance agent to determine those all-important insurance details!

Whether you are thinking about building a treehouse to be used as a retreat, a bed & breakfast, an addition to your home or your actual home, the decision to ‘go out on a limb’ and build a tree-home of your own, will quicken your imagination and awaken your creative juices in ways you have never experienced!  May your finished tree-home be not only fully functional and a truly customized environment, but once you feel the fanciful and magical elements associated with living in a treehouse, you’ll realize the “kid” in you never, ever left!