Seven stage treehouse design process

There is a lot to learn about treehouses before you start building if you want a safe, long lasting and economical structure. This seven stage workflow will guide you quickly through the basics with links to other parts of the site to find out about a topic in more detail.

1. Check the planning/building regulations in your area
2. Design the treehouse plan before you start cutting any wood
3. Keep supports separate to the house framework
4. Allow flexibility in the supports if you use more than one tree
5. Use single large bolts for attachments to the tree
6. Avoid restricting tree growth
7. Build as much as possible on the ground

1. Check the planning/building regulations in your area

• In urban areas planning regulations can easily demand that your treehouse is removed on safety, distraction or regulatory infringement grounds.
• Every area is different, but some general guidelines apply.
• Ask officially before you build.
• Speak to your neighbours before you start. If anyone objects it is most likely to be them. Discussing your idea will make it much easier to get their approval.

2. Design the treehouse plan before you start cutting any wood

• Map the supporting trunks or branches at your proposed floor level. Use string to mark the height on each trunk and draw the layout on squared paper.
• Work out the best support method.
• Lay out the floor.
• Draw the house to fit on the floor. The free Google Sketchup software works well.
• Involve the client. If the treehouse is for your children, ask them what features they would like and let them help with drawing up the plans. Make sure they feel that it is their own treehouse.

3. Keep supports separate to the house framework

• Aim for a level floor capable of taking the entire weight of the house. It is much easier to build a rigid house on a solid, flat floor than to rely on other parts of the tree for support.
• Avoid fixing any walls or parts of the roof to branches passing through.
• Walls need to be rigid enough to support their own weight plus the roof.

4. Allow flexibility in the supports if you use more than one tree

• If more than one tree is used they must be allowed to move in the wind or the treehouse can be easily damaged.
• Use either metal brackets or cables to allow flexibility.
• Building between two trees is the easiest system for large treehouses. More trees means allowing movement in different directions, which is hard to absorb.
• A popular flexible design uses a rigid floor unit that can slide over the beams below, allowing the beams and the trees to move.
• To reduce excessive movement, bolt one part of the supports to the largest tree of the set, allowing the other end(s) of the support(s) to move flexibly.

5. Use single large bolts for attachments to the tree

• Single puncture wounds at each attachment point cause much less tree damage.
• Large bolts are much stronger than screws or nails.
• Lag bolts are preferable to through bolts as less damage is caused.
• Check fastening ratings and always overbuild each joint to take at least three times the projected weight of materials and occupants

6. Avoid restricting tree growth

• Don't tie straps or ropes around the tree as this will strangle it over time.
• Add spacers between beams and the tree to allow room for growth during the lifespan of the treehouse, or use very large bolts which have plenty of the shaft exposed and mount items on the end.
• Allow a 2" gap around the tree if it passes through the floor
• Add at least a 3" gap around the tree if it passes through the roof (more if the tree flexes much in the wind)

7. Build as much as possible on the ground

• Design the treehouse in separately built sections that can easily be joined together - supports, floor, walls and roof. These can then be pulleyed into the tree and quickly secured in position.
• Using power tools is easier.
• Building on the ground is safer.
• Parts will be prepared faster and more accurately than if constructed in the tree.
• In remote locations prepare a proper work area before you start.