Treehouse Masters
Nelson Treehouse and Supply
Nelson Treehouse and Supply
How do I get a treehouse built?
We kindly ask that you fill out this short questionnaire so we can learn a little more about your vision and see if our company might be a good fit for your project. We review each submission thoroughly so please be patient while awaiting a response. We look forward to talking more...until then, to the trees!
How much does a treehouse cost?

To give you a better idea of the realistic costs associated with a Nelson Treehouse, we have broken down the base cost of an out-of-state treehouse build:

Square footage construction price: $525.00 per square foot (200/sf treehouse = $105,000.00)
Logistics for out-of-state travel costs (e.g. plane tickets, freight, accommodations, etc.): $30,000.00
Custom design by Pete Nelson: $15,000.00

Therefore, the average starting cost of a custom NT&S built treehouse is $150,000.00

Do you build treehouses as full time residences?

We do as long as you are prepared to live a semi-rustic, tiny house lifestyle! The average size treehouse we build is about 260 square feet. That being said, we have built full time residences which consist of a sleeping loft, and a great room with small kitchenette - totaling approximately 400 square feet. We do not build 1,000 square foot houses with 2+ bedroom treehouses with sitting rooms, living rooms, bathroom and dining rooms.

Please note that permitting for a full time residence is not always a straight forward process and may take considerable time and effort to obtain. Also, in order for amenities like running water and power to be installed, infrastructure like a septic system, and water and power hook up must be established on the property.

What about permitting?

Nelson Treehouse and Supply does not secure building permits for you [we do not encourage you to circumvent laws and/or ordinances.] This section is for informational purposes only. We can, however, help you along the way, if you choose to obtain a permit, by coordinating with architects and engineers to see the project through.

Obtaining a permit for a treehouse is, in most cases, not straightforward. There are many factors that can complicate the process. Because of the fact that regulations are different in every town/city/county/state rules can vary from zero regulations, 200/sf maximum to nothing built more than 5 feet off the ground, we cannot list the rules and restrictions for all the municipalities that oversee building projects. You must perform your own due diligence in that regard. We can offer some words of advice based on past experience.

Consider your neighbors:
Regardless of whether your local governing body allows treehouses to be constructed, you should consider how your project will affect your neighbors. Will your new, loftier view invade their privacy? Will your structure obstruct their existing view? Whenever possible, the best bet is to locate your treehouse in a place where neighbors will support your effort rather than try to stop it.

Consider the consequences:
Hefty fines and/or an order to remove the structure can be imposed upon unpermitted projects. If you choose to proceed without a permit, make sure to build the treehouse according to engineered specifications that ensure the integrity of the structure. If authorities get involved after the treehouse is built, proof of structural integrity will go a long way toward making the case that your treehouse is safe.

Consider your options:
If you are looking for property with the intention of building a treehouse you have the luxury of checking the building codes for each area in which you are shopping and could theoretically buy a property where you know you will be allowed to build a treehouse.

If you already own property, find out what the rules are regarding size and height. Some cities or counties do not issue building permits for structures less than a certain number of square feet. Others permit any "out-buildings" that will not be used as a dwelling. And maybe you are one of the lucky few who live in a part of the country that requires no building permits whatsoever!

If you are denied a permit to build a structure in a tree, consider building a structure on posts or "ground mounted struts," as some engineers call them. This can often be done near or amongst the trees, so you still have the feeling of being in the trees Keep in mind that any additional building requirements for your area. Are there required setbacks (riparian zones, property boundaries etc.)? Are there height limits? Restrictions in your locality that apply to houses built on the ground likely apply to treehouses as well.

What are the basic DOs and DON'Ts of treehouse building?
  • Always treat the tree with respect- it is a living organism!
  • Use single, large bolts or TABs (treehouse attachment bolts) for main supports.
  • Line bolts up (vertically) on the tree if using more than one bolt - it is better to disrupt only one channel of nutrient flow. When doing this, keep the distance between the bolts about 18 inches apart and never less than 12 inches. This allows the tree to treat the second bolt as a separate wound. Both wounds will be compartmentalized separately by the tree, thereby reducing the risk of rot between penetrations. If the penetrations are too close to each other, the tree will treat them as one wound and rot could set in between the bolts, increasing the chances of pull-out.
  • Drill the correct sized hole carefully with a sharp bit to minimize damage and leave a clean wound.
  • Let any part of the treehouse come in contact with the tree directly. The entire treehouse should rest on the support system. Otherwise the tree will suffer wounds when the structure sways in the wind. The same applies to ropes and cables, the constant rubbing against the bark destroys the living tissue and open the tree to possible infection. A particularly bad method is to rest one end of a support in a fork of the tree to theoretically allow the treehouse to move in the wind. This causes massive damage due to the motion and weight bearing down on the surfaces in contact.
  • Cut away excessive amounts of bark or wood to provide a flat surface. This is the tree's natural armor and it is necessary for the vitality and strength of the tree.
  • Use nails for main supports-- they are much weaker than bolts, may work loose and require more penetrations to do the same job as a single bolt, causing the tree to suffer more overall damage.
  • Do not use cables or ropes wrapped around branches for support. These wear away at bark and sensitive layers below, and as the branch or trunk grows it will strangle and cut off nutrient flow to the rest of tree.
For more information, consider purchasing our Treehouse Instructional Guide which dives into everything from tree selection to platform design.
What are some materials and products regularly used by Nelson Treehouse and Supply?

Be in a Tree (the "supply" in Nelson Treehouse and Supply) assorts the heavy duty, custom fabricated hardware needed to build in the trees safely and sustainably.


Nails are a thing of the past! We use Screw Products Inc for almost all of our fasteners. These are also assorted at Be in a Tree.

Hog Wire used for railings and fencing:

The material you are looking for is what we call "hog wire" or wire mesh. It is a " gauge with 4" x 4" square spacing. Your nearest lumber yard or feed store should be able to help you find the right stuff. We encase it in our lovely Western Red Cedar to form a panel.

Do we have plans for this? Not currently.


The cork we tend to use is sourced from a company called Cali Bamboo.


Polyurethane is generally used for interior finishes. However, it is important to note that it has a long dry time and leaves a lingering odor. That being said, it does leave a beautiful sheen and protective layer on the wood.

We prefer penetrating oil products to protect the exterior of our treehouses. Our go-to product is Penofin (PENetrating Oil FINish). Penofin Blue can be sprayed, but we prefer brushing or rolling, which encourages the product to soak into the grain of the wood (sprayers can be wasteful). Penofin Verde is a more environmentally friendly option, and is odorless. It is great for interiors, however it cannot be sprayed.

Latex paint is also fine for exterior finishing, but we prefer to showcase the natural beauty of the wood rather than cover it.


The net structures featured at TreeHouse Point and on Treehouse Masters are made with recycled fishing nets. Check them out at Unfortunately at this time we do not have any instructional plans for them.

Where can I buy Pete Nelson designed plans for treehouses?
We assort many plans designed by Pete on our online store - a one stop shop for all things treehouse related. What an ideal summer project!
How do I get a treehouse consultation?
Please start by filling out the online questionnaire to enter your request into our system.

Phone consultation services are offered at an hourly rate of $150 (billed in 15 minute increments) with a one hour minimum.

Local consultation services are offered at an hourly rate of $250 (billed in 15 minute increments) with a one hour minimum + a $0.75 per mile travel fee.

How do I decide what tree to build in?

The design process begins with the proper selection of a healthy tree that will continue to thrive with a treehouse attached to it. Here are a few of the factors we consider when choosing a tree fit for a treehouse:

- species
- trunk diameter
- distance between trees
- proximity to utilities
- proximity to main house
- wind, sun, and view considerations
- approximate height of treehouse
- any proposed add-ons or approaches (stairs, bridge, boardwalk, ramp)

The health of your tree is crucial to the safety and longevity of your treehouse. As well as Pete knows his trees, he still strongly recommends that you enlist the help of a local arborist to evaluate the health of your trees. An arborist can also identify any work that might need to be done to prepare the site for your project. And, once the treehouse is erected, assist with maintenance to ensure the health of the tree. A healthy tree = a happy treehouse. Clients who live in the NorthWest region can check our Resources page for arborists that Nelson Treehouse and Supply has experience working with. Another good resource is the ISA when looking for a certified arborist. If you would like more indepth information on the trees that we recommend for treehouse use, please refer to our Treehouse Instructional Guide.

What do I need to know about designing a treehouse?
The key to a successful treehouse building is safety. A structurally sound treehouse in a well maintained tree has the potential to last as long as the tree!

Engineering your treehouse:
We highly recommend hiring a professional engineer when designing your treehouse to ensure that it is structurally sound.

Tree-through structure:
We typically do not design treehouses with trees penetrating the roof because there is no good way to create a fully waterproof seal between the roof and the tree. Our suggestion is that you use a flexible collar that fits around the tree. The key is flexibility in the collar so that the tree is not be girdled over time. Make sure that any water traveling towards the opening is diverted by a valley or "cricket."

If your treehouse is the highest point in the surrounding area then, lightning is a concern. Some people choose to install lightning rods. We suggest consulting with a local lightning rod contractor if you are concerned. Ideally, a lightning rod would be used in a tree other than the one supporting the treehouse.

Knee Braces:
There is no "one-size-fits-all" single-tree knee brace. In the simple for a typical knee brace is composed of a piece of timber (4x6, 4x8, etc.) oriented in a diagonal position. It is attached at the top (the structure end) bottom (the tree end). We use a combination of paddle tabs and lag bolts for this task. It is recommend that you read up in our Treehouse Guide for more detailed instructions.

Tree Layout:
Tree Layout is one of the most important steps to building your dream treehouse. To learn more about how to go about this please refer to our Treehouse Instructional Guide.

Although all tree layouts are different, there is always room to modify. For those DIYers who have carpentry skills, we have plans for you. Additionally, we offer consultations to help with that initial platform modification.

We have our most commonly used hardware for sale at our store. We also offer certain hardware packages that correspond with our Plans and can fabricate any custom hardware you might need for your special project. If you are considering purchasing hardware, we strongly suggest you purchase the Treehouse Instructional Guide as well.

At this time we do not have any companies or contractors that we would recommend for bridge building. Unfortunately, since it is such a situational application, we do not offer consultations on the matter.

What if I don't have trees?

Not everyone can have the perfect backyard tree. If your tree is small or not suitable for bearing the load of a treehouse, we would not suggest building in it. It is possible to achieve a structure that is a treehouse in spirit by posting down to create an elevated house. We would recommend faux trees for the "treeless" projects. They can look just as attractive as real trees and hold a pretty heavy load- if done correctly.

There are a number of companies and resources out there that deal only with post supported houses.

Where can I stay in a treehouse?
At Treehouse Point, our bed & breakfast, located just 25 miles east of Seattle! Please check out You are also welcome to send a short e-mail to for an auto-reply containing information regarding rates, tours and availability.
Where can I send fan mail?
We love hearing from our fans! Please send any fan mail to:
Nelson Treehouse and Supply
PO Box 1135
Fall City, WA 98024