Using permaculture ethics & design principles to transform an old energy guzzling bungalow into a showcase of sustainable design. It's about energy cycling, building community, self-reliance,creatively using & reusing materials... all without spending heaps of money.

Monday, September 19, 2011

Building a treehouse

Principle 11: Use edges and value the marginal

The tree house, which should soon be overgrown with new foliage
I had been wondering whether or not to remove this large tree from the backyard for some time. I've had it identified by a couple of people but never written down the name and forgotten it promptly. It's an elm of some descrition I think and I'm pretty sure that it's considered a weed. It's a fast growing and brittle timber, very light like balsa wood. I prunned it heavily to about a third of it's height about a year ago.
There have been a few good reasons why I've kept it, even though it shades out my minimal prime vegie growing land. It's deciduous, providing shade in the summer for the kids to play under, it can provide an ongoing timber source (firewood, garden use) and I saw potential for it to become the base for a tree house for the kids. Creating space where there wasn't any before - important stuff on a small block.
After a year or so of mulling over the idea of a tree house I decided to do it. I got inspired into action by a mate who built one for his kids, "even though there were plenty of other important jobs to do", you've got to do these things before the kids grow up. I was keen to get the job finished before the new growth started so that it would eventually soften the stark project.
I had the idea of using chains to suspend the floor joists. There are three joists, the middle one sits nicely within two opposing forks in the tree, which just happen to be near on level. The other two have a direct connection to the tree at one point and hung from a chain at the other. One of the advantages with the chain that I see is that it can be adjusted as the tree grows, to help keep the floor relatively level. The joists were fixed together to make the base frame, painted with linseed oil and strips of cement sheet were fixed on top before flooring was laid, to help prevent rot. 30mm x 90mm timber was used for flooring to give added strength and longevity. Uprights positioned and corrugated iron fixed for walls, which brace it well. Then it was painted with linseed with the help of it's new owner.
It feels very sturdy and can easily hold the weight of a couple of adults. A lot stonger than the tree houses I made when I was a kid. I think that it should last as long as the kids should want to use it... then I got thinking wouldn't make a great platform for a urban beehive?

Two chains were used to suspend floor joists
Cement sheet offcuts were used between the timber to help its life

Thick hardwood (old wall studs) timber flooring painted with linseed oil

The grand opening on Kai's 4th birthday

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