How to Build a Tree House
Tree houses are for kids of all ages. The sensation of being high up in a tree is as exhilarating for a 50 year old as it is for a 5 year old. At least it is for me.
What makes the perfect garden? Aspect, vistas, flower beds? In my case high up the list would be mature trees, positioned the right distance apart for a hammock and at least one of them strong enough for a tree house.
For me the best type of tree house is one which is attached only to the trunk. This requires a healthy tree with a near vertical trunk of at least 30cm diameter.
With a tree like this it is possible to build a platform which will move with the tree in the wind, thereby giving a real sense of being up in the canopy.
The key steps are:
- Design. As with so many DIY projects this is much the most important stage and will depend on the tree’s shape and size and the timber you have available. The important considerations are safety, access and style. You want it to be high enough that you feel in the canopy, but not so high that it is dangerous. In our case the platform is 3m high and it is accessed by a rope net and by a slide.
- Beams. The main strength comes from two pairs of 8x2” beams. The first pair sandwiches the trunk in one direction and the second pair rests on the first pair and sandwiches the trunk at 90 degrees to the first. Each beam should be horizontal and fixed to the tree trunk with at least 2 coach bolts of around 20cm length. This will require drilling of a good sized pilot hole.
- Frame. Four more 8x2” timbers are needed to form the box frame. The top two beams should sit within the frame and be screwed to it and the frame should rest on the lower two beams. The lower beams can be attached to the frame with L shaped brackets.
- Braces. To prevent the platform from tilting, each corner of the frame should have a 3x3” brace attaching it to the trunk at around 45 degrees. I used U shaped joist brackets to attach the brace to the tree trunk.
- Platform. Decking boards should be spread diagonally over the top of the frame and screwed into frame. Use a jigsaw to make a hole for the tree trunk (allowing space for growth) and to trim the overhanging boards.
- Fence. The type of fence will depend on the level of safety you want. We were happy to attach fence posts to the frame and then to hang rope between the posts. If this makes you nervous then you might prefer to make the fence solid.
You should then have many years of pleasure from your tree house. The only factor we overlooked was the ‘sail effect’ of the platform. One winter we had exceptionally high winds, which tilted the tree so much that the platform became a sail and caused the tree to blow over. With the help of a tractor and a few ropes we were able to pull it back up though and the tree and tree house have been fine ever since. We did concrete in some railway sleepers though to prevent it happening again.
Last tip, check it regularly.