Garden treehouse

The treehouse left our Surrey workshop in pieces, strapped down on a lorry, and the next time I saw it upright it was standing in a garden in Portugal with the lawn running out in front of it. Seven days from the first pole going in to the last window going on. People are usually surprised by that. There isn't a trick to it - we just do the difficult part at home, before anything is packed, so the work on site is assembly rather than invention.

What the family asked for at the beginning was simple enough to say and harder to draw. They wanted somewhere raised, with a proper view back across their own garden, and enough going on around it that the children would actually use it rather than admire it. That was the wish-list. The tree they had was a good one, so we put the treehouse underneath it and carried the load on poles instead of the trunk. This is the question most families ask before anything else, and the honest answer is this: a treehouse does not have to hang off a tree to belong to it. Poles take the weight. The tree goes on doing what it was doing.

Then the windows. We built them into the walls rather than leaving the sides open, which changes what the thing is - a small room up in the air instead of a platform with a rail around it. Children treat a room differently. They stay in it. A slide, a zip wire and a rope bridge take you back out of it again, so the garden gets used in a loop rather than in one spot. The clients were happy. I wonder now whether the part they'll remember is the height, or simply having somewhere to sit and look at their own lawn from…