8 Tips for Building a Treehouse
Ready to build your kid the coolest treehouse on the block? Start here with all the info you need, including pro tips and plans!
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Where Should You Build a Treehouse?
The first step is finding a sturdy tree that can handle the construction. Ideally, there’s a hardwood tree in your yard old enough so its branches are eight or more inches in diameter.
If you only have softwood trees, the branches will need to be bigger to ensure that they can handle the load. Ideal species include maple, oak, fir, beech, and hemlock.
Keep Weight and Stability in Mind
Despite the fanciful treehouse plans you may have in mind, a few practical structure designs will be necessary:
- Your platform should be as close to the trunk as possible. You don’t want your kids falling out of the treehouse. Also make sure the platform is adequately braced. Ideally, you should add diagonal bracing to account for any uneven loads.
- Keep the load centered over the base of the tree. If you put it only on one side, it won’t be stable.
- If you’re planning on building big and heavy, try to spread construction across multiple trees instead of just one.
- If you live in an area with high winds, keep the treehouse to the lower third of the tree to prevent uprooting in a storm.
- If you’re building on one trunk, do your best to keep the main platform level. Accomplish this by supporting the beams from below and cantilevering them.
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Don’t Restrict Tree Growth
- Leave some gaps around the tree to allow for growth, especially around branches and trunks that come into the house. A good rule of thumb: Two inches if the tree passes through the floor, and three inches if it passes through the roof.
- Avoid using anything that constricts the branches (e.g. rope, straps, wire, etc.) or you risk strangling the tree.
- Include spacers between the beams and the tree to account for movement.
- Consider extra-long large bolts. This gives you the freedom to mount items on the ends while also giving the tree room to grow.
How To Level a Treehouse Floor
A treehouse, especially a large one, needs a stable floor. You’ll need to center it over the trunk and allow the weight to be spread across multiple branches.
Once you’ve built a level floor, you’re in good shape to start building the walls and roof. Don’t be afraid of using shims so your beams lay evenly across the branches.
Build Sections on the Ground First
The safest way to build a treehouse? Do as much as possible from the ground first, then lift things into place. But if your tree has branches that will penetrate the structure, you may need to build those pieces in the tree. Once you complete the structure, let your kids decorate the room(s) however they want.
“I assembled the platform and house on the ground, then disassembled them,” says treehouse builder Bob Lackey. “After attaching the supports to the trees, I lifted the platform piece by piece and assembled it on the supports. An extra set of hands was needed only to raise the four walls and two roof sections. Final assembly took place in the trees.”
Use the Right Fasteners
- Make sure that you’re picking flexible supports. This is especially important if you live somewhere windy, or if you’re using multiple trees. You don’t want your treehouse preventing the trees from moving in the wind. Special floating brackets allow this. They can be pricey and may require specialty tools to install, but they can handle more weight than other bolts and give the tree room to grow.
- Opt for lag bolts wherever possible to avoid unnecessary damage to your tree.
- In that same vein, don’t be overzealous with your fasteners. The fewer holes you put into your tree, the better. Aim for large bolts over smaller screws or nails. Choose 1- or 1-1/4-in.-dia. lag bolts, which are ideal.
- Try to build your house on top of fasteners instead of directly on the tree. Again, the tree needs room to grow.
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Be Conscious of Treehouse Safety Issues
Even the most carefully built treehouses will damage the tree they’re in. The increase in foot traffic around the base compresses the soil, harming the roots. So does adding weight to the branches. And holes in the tree from fasteners can become infected.
If you have a particularly beloved tree, don’t risk the damage. Pick a different tree to build in.
How to minimize tree damage
Take these precautions:
- Use ground supports to take some of the weight off the branches
- Think carefully about each hole you put in the tree and make sure it’s really necessary before drilling.
- Spread out your fasteners at least 18 inches apart vertically and at least 12 inches apart horizontally.
- Avoid throwing cables or ropes over the branches, which can damage the bark.
Neighborhood concerns and municipal regulations
Depending on your neighborhood, you may need a permit. Check your local laws before building. It’s also a good idea to check with your neighbors to make sure everyone’s OK with it. Avoid building your treehouse in a place that might infringe on their privacy or property.
To keep your kids safe, we don’t recommend building taller than eight feet. We also strongly urge you to build adequate safety railing. And warn your kids to stay out of the treehouse in a storm, especially if there’s lighting or strong winds.