What better way to encourage your kids to put down the iPad and get into the garden than by building them their very own treehouse? Not the easiest of DIY projects by any means, it’s definitely one of the most rewarding.
Because every tree is different, it’s impossible to provide a detailed plan for building a treehouse – the support system needed will depend on the individual tree. However, whatever type of treehouse you’re planning, there are some simple steps that you should follow before getting started.
Do your research
Unfortunately, treehouses aren’t suitable for all gardens. Before you get out your hammer and saw, make sure that you:
1. Check whether you need planning permission. Strictly speaking, anything with a raised floor more than 30cm from ground level requires permission, however, some local authorities take a more lenient view of children’s play equipment.
2. Identify a suitable tree. You need a strong, sturdy tree with roots that are deep and well established, and that’s not showing any signs of disease or parasites. If in any doubt about the suitability of your tree, ask an arborist to inspect it before you start building. To ensure a strong base for your treehouse, it’s best to build it across two or more trees, or a single tree where two sturdy branches separate into a V shape.
Designing the treehouse
A safe, strong and reliable treehouse requires some careful planning, so before you even think about getting stuck into the construction, make sure you’ve really thought through the design.
3. Draw a diagram of the treehouse – it may be helpful to even make a cardboard model of it to help you identify any potential issues. Be sure to measure and mark all supporting or intruding trunks and branches.
4. Design a treehouse that can be built mostly on the ground. It’s much easier and safer to construct different sections of the treehouse on the ground and then hoist them into position: using power tools up a tree should be avoided as far as possible.
5. Decide which support method to use. The most common way to support a treehouse is to bolt the support beams or floor platform into the tree, although you could sink support posts into the ground close to the tree, rather than attaching anything to the tree itself.
6. Don’t restrict tree growth. When designing your treehouse, make sure you take tree movement and growth into consideration by allowing 5-10cm gaps around any branches or trunks that penetrate the treehouse.
7. Safety first. Don’t be tempted to build the treehouse too high into the tree – the higher it is, the more vulnerable it is to wind; 1.8m-2.4m is usually about right. Make sure that your treehouse has a safety railing all the way round, at least 90cm high with balusters no more than 10cm apart. And think about covering the area around the treehouse with a soft natural material like wood mulch to cushion any falls.
8. Think about how the treehouse will be accessed. Easy to overlook, make sure you give thought at the start to how your kids will get into the treehouse – can they just climb up, or will they need a ladder or a staircase to get in?
Selecting your materials
A treehouse really is the sum of its parts – scrap timber and a few nails won’t do the job, so you’ll need to think carefully about exactly what materials you need.
9. Calculate the depth of wood that you need. You’ll need to make sure that your beams will be strong enough to support the treehouse. Generally, the depth of the timber should be at least 3 times the width, but ask your timber merchant for advice before purchasing.
10. Choose which supports to use. If you’re supporting your treehouse with a single trunk, you can get away with fixed supports, but if you’re supporting it across multiple trunks or trees, you should use flexible supports to allow for movement in strong winds.
11. Use bolts rather than nails. Your treehouse will be subjected to a lot of stress from both the people playing inside it and the weather. As such, use galvanised bolts rather than nails to fix your supports as they’re far stronger. You can buy treehouse attachment bolts which are specifically designed for treehouse construction.
There is a lot to think about when planning and designing a treehouse, but as with most DIY jobs, the more thought that you put into it before getting out the tools, the better the result is likely to be.