Nothing is more exciting for a child than the prospect of a treehouse in the back garden. Perched up high in the branches, a treehouse allows a child (or just those who are young at heart) to daydream, escape from reality, and use the power of their imagination. Your children can play games, use their imagination, and create timeless memories as they delight in their own personal palace in the sky. And yes – many adults love them, too – one of the world’s leading treehouse construction companies builds most of their creations for adult use.
Treehouses run the gamut from humble wooden boxes suspended between two trees to majestic wonderlands, straight out of Never Never Land. Just check out some of these fantastical tree houses from around the world! Even if you don’t have the time, skill, or trees to build something this over the top, your kids will love any treehouse. Whether you climb up after your kids, or you relax on a lutyens bench down on the ground, it will be a special feature to your garden that everyone can enjoy.
No matter which style you plan to build in your back garden, start by thinking about the following tips. Happy building!
Most councils across the UK have rules around the construction of a treehouse, requiring full planning permissions. The building process, materials, and plans are often treated just like any other construction project. In this case, you will need to seek planning permissions. You must also check your title deeds. Some have restrictive covenants that forbid the construction and/or installation of any structures (including sheds and other outbuildings) on your property.
It’s important to note that some experience in construction is important. While you might be imagining a simple and fun project for you and your kids, the structural integrity of a treehouse is actually really important. After all, if your treehouse is not sturdy, safe, and strong, the health and safety of your most precious cargo – your children or grandchildren – is at risk. If you do not have previous experience with construction, you should always hire a professional to take on the job, or help you with the process.
If you are considering building a treehouse, you will need to assess the trees in your back garden. You might see a whole host of plans online or gain inspiration from your neighbour’s cool treehouse, but don’t get too attached to the design until you know what will work for your trees. The width and sturdiness of your trees, the distance between them, their proximity to your house or a fence, and the height of the branches – these factors will all dictate the height, size, shape, and design of your treehouse.
Trees are living and growing entities. As time passes, your trees will continue to grow and change, and so any construction plan needs to allow for the future growth of your tree. Never cut away large branches or chunks of the trunk in order to support your tree house, as this can make your tree vulnerable to disease and infection. Ideally, your construction techniques should be designed in a way to bolster and support the tree, protecting it from damage for decades to come. You can use Treehelp.com (Tree Care Made Easy)
the kids should be involved. The building of a treehouse was an important selling point when we told our boys we were moving out of the big, exciting city to a sleepy rural town. I still have our older son’s hand-drawn plans for what he wanted it to look like. (It’s close.) And they both drove some nails and screws and found some cool branches that we incorporated into the design. They participated. 
Your first step in constructing your treehouse is to build the platform, as it forms the support system of the structure. Anchor the platform close to the trunk, ensuring that you allow some extra space for the tree’s future growth. It should be level to the ground, and have a central balance.
Don’t use nails to affix your platform to the tree, as they are weak and loosen easily over time. As you will need to use plenty of nails, there is a good chance that they will damage your tree. Instead, use large bolts. Over time, your tree will grow and expand over the bolts. This process creates a tight bond called compartmentalisation, and makes the structure even stronger.
You could also use Garnier Limbs, which are artificial tree limbs made from steel, invented by treehouse professional Michael Garnier. You bolt these limbs to the tree, and they can hold up to 3600 kg, which increases the safety of your treehouse.
Now that you have considered all of the points above, it’s time to present a simple guide to building a treehouse. We like this rough design plan, because it only requires a minimal amount of bolts to be driven into the tree. We recommend that you build this treehouse on a double trunk tree to add stability and strength to the structure.
Measure approximately 3 or 4 metres up from the ground on each of the two tree trunks. Use 3 pressure-treated 2 x 12 inch boards, and fan them out at this point. Place one joist on the outside edge, and thread one through the central V. Support the outer ends of the joists with posts and clamps in order to keep them steady.
Drill 5/16-inch holes through the joists, and thread ¼-inch-diameter x 3-foot-long galvanised steel threaded rods down through all of the 3 joists, but not the trunks. Secure the 2 x 12 inch boards to the trunks of the tree by affixing nuts and washers to the rods. Tighten with a wrench. At this point, the 3 floor joists should be splayed in the air.
With a cordless impact drill, screw the joists to the tops of the 4 x 4s and use GRK 3 1/8-inch structural screws. Consider pre-boring the joists with screw-shank clearance holes in order to ease the process. With 3-inch galvanised decking screws, attach the 2 x 4 struts to the posts. These struts will add support and rigidity to the frame, preventing wobbling and shakiness.
Once all of the posts and joists are secure, install the platform. Screw 2x pressure-treated lumber lengthwise along the joists, and fasten the floorboards with 3-inch decking screws.
Now that the structural work is complete, it’s now time to really customise the build and make it your own. Get the kids involved at this stage – even the littlest ones can pick up interesting branches from the garden, paint details, and make their own decorations to add. Now is also the time to assess the structure for stability. If you notice a shaky corner, fasten a wood block in place for extra support.
Remember – even the best laid plans are fallible. You are working with the natural world, and no matter how much you want a specific design or idea to work, branches will get in the way, the wood will ‘misbehave’ and certain things will have to be altered or adapted. Remember to enter into the treehouse build with an open mind, and be prepared to be flexible. The end result will be completely your own – or, even more accurately, your family’s – favourite place to play, daydream, and hang out.
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Trimarchi, M. (2008). How Tree Houses Work. [online] HowStuffWorks. Available at: https://home.howstuffworks.com/treehouse3.htm [Accessed 22 Feb. 2020].
Wallop, H. (2009). All tree houses need full planning permission, new rules say. www.telegraph.co.uk. [online] 6 Jul. Available at: https://www.telegraph.co.uk/news/uknews/law-and-order/5749382/All-tree-houses-need-full-planning-permission-new-rules-say.html [Accessed 22 Feb. 2020].
Anna is the marketing and office manager for Garden Benches – a premium supplier of high-quality wooden benches and other outdoor furniture.