You’re not the first to wonder how to build a backyard treehouse without trees for support. While it may sound counterintuitive, it’s definitely possible. It takes a lot of hard work, careful planning and plenty of nails, but it’s possible.
In some ways, it’s easier than constructing a treehouse up in a tree because you’ve got more control over the structure and its supports.
There are various reasons to build a backyard treehouse without tree support. Perhaps you don’t have many trees in your garden or the ones you do have are too small.
They might be positioned far too close to your neighbor’s bedroom windows. Or you may simply feel safer letting your children use a treehouse built on stable ground.
Whatever your reason, the best method is to create a freestanding platform using wooden or metal poles.
This is the safest way to create an artificially raised base for your treehouse to sit on. (1) Sink four sturdy posts deep into the ground where your treehouse will sit, (2) secure them with concrete, (3) attach a wooden base or platform to the posts, (4) build your treehouse on top of the platform and, finally, (5) add any accessories such as stairs or fencing.
Provided the platform’s posts are sunk securely, building a backyard treehouse without tree support is safe and straightforward. What’s more, it gives children extra room, space for an outdoor deck and enough height to feel like they’re kings of the world.
Nevertheless, building any type of wooden treehouse is a significant project. It’s important to adhere to trustworthy guidelines and take all the necessary steps and checks to ensure your DIY hideout is safe.
There should be no planning conflicts, as your treehouse won’t have a foundation. However, you should still consider privacy issues when building close to neighboring houses.
Table of Contents
Things to Consider When Building A Treehouse
This next section discusses the construction materials you’ll need, any factors you should consider when planning the build and what type of measurements are suitable. It also offers advice on high quality products to help you get started right away.
If you need ideas on how you want your treehouse to look, as well as building techniques, check out a really good book on Amazon called Black & Decker – The Complete Guide to Treehouses: Design & Build Your Kids a Treehouse.
We’ll explore basic treehouse construction in more depth later (that’s the easy part). Let’s concentrate on getting your treehouse up off the ground first.
Once you have a safely raised platform, the possibilities are endless. You can build a backyard treehouse as simple or as lavish as you prefer.
Can You Build A Treehouse Without A Tree
Yes, and it’s probably easier than putting one up in a tree because you’re building on stable ground as opposed to narrow, flexing branches. Weight distribution isn’t an issue in the same way it is when trying to find anchor points on a tree.
Picture a traditional backyard treehouse. Any part of the base not firmly attached to a tree branch needs an anchor point elsewhere such as in its walls.
The challenging part is creating enough points of contact (between the tree and the house) to ensure it always stays firmly attached. One alternative to a fully suspended base or platform is a very tall platform – with extremely tall poles – that stretches from treetop to ground.
Or you can keep things simple and safe with a freestanding construction. If built correctly, traditional treehouses can be very secure. However, there will always be risks you cannot control.
With a freestanding treehouse design, there’s no worries about branches breaking in extreme weather or floorboards bowing beneath rambunctious feet.
Before you begin building a backyard treehouse with tree support, check out the local regulations. In some areas, there are setback rules that require any new structures to be positioned a certain distance from neighboring properties.
In other areas, treehouses are considered ‘accessory structures’ with legal limits on height and floorspace.
How Much Does It Cost To Build A Treehouse For Yourself
It’s difficult to come up with a cost estimate because there are so many variations among treehouse designs. Families have successfully constructed backyard treehouses for $800 or even less.
If you can salvage wood and other materials at no cost, the expense is going to shrink significantly.
It depends on a host of factors such as the size of the treehouse, type of wood used and whether the interior is fully or partially finished. Add extra for things like safety stairs, fences, railings and other accessories.
The national average cost of building a backyard treehouse is $7,000. This is for an (approximately) ten-foot house with complete walls and a roof but an unfinished interior.
The average cost of a ten-foot treehouse without complete walls or a roof (but with safety railings and stairs) is $4,000.
The average cost of a ten-foot treehouse with complete walls, a roof, a deck and a finished interior is around $15,000.
As you can see, there’s a lot of wiggle room. If you’re on a tight budget, careful planning is essential. Know exactly what construction materials you need, in what volumes and at what expense before you pick up a hammer.
One of the biggest expenses is the cost of lumbar. Do not use cheaper pressure treated varieties if any part of your freestanding treehouse will be touching your backyard’s trees.
Chemicals in the wood have been known to bleed out and damage the health of living trees when they make contact. This is only an issue if you’re building a freestanding structure that’s nestled against trees.
Cedar, cypress and redwood varieties are among the best options for children’s treehouses though they can all be pricey. Of the three, cedar wood is the most expensive at between $8 to $20 per square foot.
Cypress wood is the most affordable at anywhere between $4.50 and $5 per square foot. Redwood is somewhere in the middle depending on where it is sourced.
What Is A Good Size For A Treehouse
Again, it depends on the type of vision you have for your DIY treehouse. Most families stay below ten feet in height (from the ground). Even with safety ladders and fences, accidents happen. At this height, falls are going to hurt but they’re unlikely to cause severe injuries.
The sweet spot for backyard treehouses is anywhere between seven and ten feet off the ground. If the treehouse floor is any lower than seven feet, you might have grown ups hitting their heads on the bottom.
This won’t be a problem for everyone but do be aware of this if planning a low hanging structure.
The wonderful thing about freestanding treehouses on raised platforms (as opposed to tree mounted structures) is you don’t need to worry so much about weight.
If your supporting poles are positioned and secured correctly, they should be capable of holding a much heavier build than you’re ever likely to need.
It allows you to add a lot more floorspace than you would be able to otherwise. Though, don’t forget, the size of your supporting platform sets the limit for how big your treehouse can be inside.
Its floorspace (width and length) will need to be (at least) slightly smaller than the platform’s. Whether you make the treehouse much smaller than the platform in order to leave room for a deck is up to you.
For a treehouse with an interior floor space of 8’ x 4’, you would need to use a platform measuring 2 x 6. Your posts should be 4 x 4 (or close) with a diameter of 5’’ or more.
After bolting the platform to the posts, consider filling in with 2 x 4 joists for extra durability. Lay another sheet of wood around the same size (2 x 6) to prevent twisting at floor level.
What Materials Do I Need To Build A Treehouse
Building a backyard treehouse without tree support requires high quality materials. As the structure will be raised off the ground and supported by four poles, the wood needs to be structurally sound and rot free.
If you’re using salvaged wood, check it very carefully for structural weaknesses.
- 20-by-1 foot pressure treated posts/poles
- Plumb bob
- Spirit level
- 300 lbs. gravel
- 300 lbs. quick-drying concrete mix
- 12 sheets of 1-inch-thick plywood
- 12 8-foot lengths of 2-by-4s
- 1/4-20 wood to wood fasteners
- Wood screws
- Power drill
- 1/4-inch drill bit
- Countersink bit
- Metal U-channel straps
These are some of the basic materials you might need to build your freestanding treehouse structure. You can add things like paint and extra wood for railings and stairs.
This list does not include wood for the roof. It focuses mainly on the base platform, floor and walls to give you an idea of what might be needed for the house’s framework.
What Should I Put Inside the Treehouse
Once the treehouse’s platform and outer frame are constructed, you can start to get creative. If you’re unsure how to decorate, get the kids involved. It’ll be their den and hideout after all.
Salvaged materials are, again, really great for this. You can also browse secondhand furniture stores and thrift shops for furniture to use.
Here are some simple items that can make your treehouse feel like home:
- Coat hooks
- A swing (hung from the bottom of the base platform)
- Lots and lots of soft throw pillows
- Twinkly string lights
- Upcycled coffee table
- Shoe rack
How To Build A Simple Treehouse Step By Step
This next section includes a step by step guide and video example of how to build a simple backyard treehouse without tree support. It’s just one way of doing things.
We recommend doing your own research to find the method that works best for your outdoor space, resources and personal treehouse goals.
The video is a good example of the construction techniques involved in building that all important base platform. Without a steady platform, you don’t have a treehouse. It’s just a standard playhouse.
Constructing the platform is a job that can be done alone, but it’s much easier if you recruit eager friends and family members to help. Alternatively, you always hire a professional contractor.
The average rate for professional labor can be anywhere between $70 and $150 per hour. It will cost more if you want the laborer to help with project planning and designs.
- Step 1 – Check your local planning department for building regulations/restrictions.
- Step 2 – Consider talking to your neighbors about the project (noise, privacy, safety, etc).
- Step 3 – Start planning your treehouse’s design/dimensions.
- Step 4 – Write a list of required supplies/materials.
- Step 5 – Begin sourcing supplies/materials. (If relevant, enquire about salvaged supplies)
- Step 6 – Build the raised platform. (Concrete needs 2-3 days to dry)
- Step 7 – Use a treehouse kit or construct your own treehouse frame.
- Step 8 – Securely bolt the treehouse to the raised platform.
- Step 9 – Begin adding accessories such as stairs, fences, slides, etc.
- Step 10 – Conduct a thorough safety assessment.
- Step 12 – Enjoy your new ‘treetop’ hideout. (Don’t forget, it’s for the kids!)
The first step is to dig a hole (roughly 4 feet deep x 2 feet wide). Carefully place a pressure treated post/pole upright in the hole. Brace the post upright using a 2-by-4.
Adjust the 2-by-4 until the post is perfectly level and straight. You can use a plumb bob suspended from a spirit level to check its straightness.
Repeat (the above steps) three more times with the three posts making sure to space them where you want the corners of your platform to extend out to.
When you’re confident that each post is safely braced, make a batch of quick drying concrete. Use gravel or a similar clean compaction rock to backfill all four holes. Then, fill each hole with concrete. It will need to dry over a period of 2-3 days.
(After the first night, remove the 2-by-4 braces).
When the concrete is completely dry and the posts are unmovable (they should hold firm against a forceful push), check the straightness of the upright posts one more time. They need to be completely level before attaching a base platform.
After the platform is created, construction proceeds in a similar way to building a house with a wooden frame floor and standard joists ($13 per joist). First, the treehouse floor gets constructed by laying plywood sheets ($25 to $40 per sheet) over the frame.
The frame is extended upward to support the walls and roof of the structure. These also get covered in plywood just as if you were erecting the walls and roof of a very basic house.
If you want to side the treehouse walls, it will cost you somewhere between $3 and $10 per square foot of siding. Shingles for the roof are a little pricier at $80 to $100 per square foot.
Adding a wooden ladder is likely to cost you around $100 assuming the accessory is fairly simple. Full staircases cost, on average, $25 per square foot.
What Type of Posts/Poles Are Best for a Freestanding Treehouse
In the above example, we referenced pressure treated posts but there are various other materials you could use instead. Let’s take a closer look at different types of support and discuss which is best for your treehouse.
Ground Contact Pressure Treated Posts
We’ll start with the most obvious choice, pressure treated posts. We picked these for our example because they’re the most commonly used material.
They’re cheap, widely available and used for constructing various types of outdoor structure such as decks, balconies and verandahs. If you’ve built an outdoor structure with a timber frame before, you may already be familiar with them.
Hardware stores sell pressure treated posts in a variety of sizes and thicknesses. We recommend 6” x 6” posts for your backyard treehouse to ensure they don’t warp after a few years of use. 4” x 4” posts are very strong, but they tend to bow with age.
Pressure treated wood is vulnerable to moisture from the ground but, fortunately, encasing posts in concrete (as explained above) is a good way to seal the sunk ends and protect them from groundwater.
The parts of the posts visible above around should also be painted with a protective weatherproof sealer.
Telephone and telegraph posts make surprisingly effective supports for treehouses because they’re extremely strong, very thick and tall, pre-rounded and designed to tolerate heavy loads.
When sunk deep enough, telegraph posts can support remarkable amounts of weight without relying on cross bracing systems.
Round poles are significantly stronger than square posts but they’re not as widely available as pressure treated posts. When purchased brand new, they can be extremely expensive.
Your best bet if determined to use them is salvaged materials. One neat thing you can do is call a local electric cooperative and ask to be put on their waiting list for scrap poles.
Telegraph poles are around 40’ long, so you may only need one or two. When making your request, don’t be afraid to share details about your construction project.
If you explain that the posts are for a treehouse, the company will hopefully give you the highest quality, structurally sound materials they can find. Always check salvaged wood for quality and safety before using it.
Metal posts are the strongest option but also the most rarely used for projects like this. If a treehouse is constructed from wood, adding metal components may damage its overall aesthetic.
Metal posts are also the priciest support option available. They are only really necessary for very large, very heavy structures. You should not opt for them unless you have the cutting, welding and fabrication skills needed to handle the material properly.
What Is A Treehouse Kit And Should I Use One
One of our favorite construction options, particularly for those who lack building skills or experience, is the treehouse kit.
Treehouse kits come in a variety of sizes. Some provide just the smaller pieces of hardware such as lag bolts, carriage bolts, RSS screws, pipe brackets, T-40 bits, T-30 bits and other items.
However, most treehouse kits are designed to be ‘build and play.’ They contain everything families need to construct a basic treehouse frame.
If you’re building a backyard treehouse without tree support, you’ll probably still need to plan and construct the raised platform independently. Then, once it’s sturdy and safe, you can use the treehouse kit to build your structure right on top.
Treehouse kits aren’t right for everybody, but they can be a major help if you’re unsure what type of wood to use or which bolts and screws are suitable.
Here are some more benefits of using prefabricated treehouse kits:
- No need to shop for all the individual materials
- Can (in some cases) end up cheaper than buying pieces separately
- Provides a starting point/guidance for those with no building experience
- A faster, more efficient treehouse building process
- Great for small treehouses
- Can be built on top of a preconstructed platform/base
Helpful Tips When Considering Building A Backyard Treehouse Without A Tree
There’s more construction work required to build a backyard treehouse without tree support. However, it’s also easier in some ways.
It’s certainly a safer method for those who have no building experience. Constructing a treehouse up in an actual tree involves a lot of careful weight assessments.
You need an understanding of weight distribution and how to identify load bearing branches while avoiding any weak points. All the while, you need to be careful around the living tree.
Drilling too deep or using chemically treated wood can kill the living structure. This leaves a treetop playhouse that’s structurally sound but progressively less ‘wild’ and authentic as the years pass and the tree deteriorates.
- Don’t put chemically treated wood up against trees as the chemicals can bleed out and harm the trees over time.
- Research salvaged/reclaimed materials in your local area. You’ll be surprised at what’s out there. It can save you a lot of money.
- Plan and design your ideal treehouse. Then, consider making it a little bigger than planned. If your children are small, it’s a good idea to have a treehouse they can grow into rather than growing out of fast.
- Use your imagination. The sky’s the limit. How about a glass panel on the floor for peeping down at the ground? Or a custom slide instead of a ladder? Lower hanging branches on garden trees make great railings.
- Don’t let the kids use the treehouse until you’ve carried out a thorough safety assessment. Have your heaviest family member jump up and down on the platform, push against the walls, etc.
Not everybody has the right trees in their garden for a strictly traditional build. Fortunately, building a backyard treehouse without tree support is something even those with limited construction experience should be able to master.
The point is there are options to suit all types of outdoor space and skillset. Whether you do everything from scratch without any professional help, call in a day laborer or use a prefabricated treehouse kit, it’s meant to be a rewarding process. So, don’t forget to have fun planning, learning and working on your project.
Sure, you’ll make mistakes. Things might go wrong. You may even need to repeat steps to ensure safety and reliability. It’s all part of building something unique and completely new for your family.