School treehouse

Woodland on a school site tends to be scenery. The children walk past it on their way to the tarmac, where the play equipment sits bolted to a rubber rectangle behind a low fence. That was roughly the situation at a school in Hounslow, and the staff already knew it. What they wanted wasn't a better playground. They wanted the trees themselves to be the place children went, and weren't entirely sure that was allowed.

So the design went up rather than out. One structure, not six separate items: a treehouse at the centre, rope bridges reaching off it, a climbing wall, a slide, a hanging basket and a cascade of decks stepping through the trees in a Fibonacci-inspired sequence. I should say something practical about those decks, because they do more than look interesting. Square platforms at even heights give a child one obvious route. Decks that grow the way things grow in a wood - each related to the last - don't. There are a dozen ways through, and nothing announcing which is correct. Timber and thatch throughout. Solar panels in the finished build.

The difficult part of a school project isn't height. It's Tuesday, and then Wednesday, and then every Tuesday after that. A family treehouse might carry four children on a good weekend. This one carries many at once, tested daily by people who find a weakness long before any grown-up does. Adventure and hard daily use pull against each other, and the structure has to hold both without the adventure being sanded off it. That question gets answered in the joints.

The school's wish-list was never structural anyway. Imagination, friendship, exploration, time outside. The children were overjoyed on the day it opened, which we expected. Games invented up on the decks, groups forming there, children choosing outdoors - that came later, and I wonder if that's the thing actually worth measuring...