The Spiral Staircase Vault

This is the roof over our spiral staircase.  I like to think that this structure might be unique in the world.  I’m sure it’s not, really, but I haven’t come across another like it, neither online nor in any book. It was an experiment.

The idea was simple: two halves of a dome with a barrel vault between them.  The problem was how to build the barrel vault part with sticks (see the Bathroom Domes album) rather than form-work, without it collapsing on our heads. A possible solution to this came to me in bed one morning………….