When Maartje Lammers and Boris Zeisser, principals of the Rotterdam-based practice 24H Architecture, bought an 18th-century fisherman’s cottage in Sweden, they were told that, because of local bylaws, they could only extend the cabin by 30 square metres, to prevent over-development in a sensitive area. So they built an “accordion” house that grows in summer and retreats into its shell in winter. They designed a 320-square-foot addition to house the dining area, kitchen, and living area. One end of the addition’s shell is constructed like a matchbox, with a drawer that slides in and out.

The original cabin is the bedroom, and the turtle-like extension can be expanded using pulleys and a retracting steel frame mounted on roller-bearings, so that the living room is projected over the stream without breaking building laws because this part of the house has no foundations and stands clear of the ground.

When the family returns south in the winter, they pull the head back in.

Via The Guardian.