The five-level house has been built on a sandstone terrace on Hart Street in Edinburgh’s Unesco-listed New Town.
It boasts a folding corner wall, sliding bookshelf ladders that glide around a secret library and a roof terrace.
Affectionately named Murphy House, the residential building was designed by Richard Murphy Architects, inspired by the work of the late Carlo Scarpa, a 20th century Italian architect.
Planning consent was approved for the home in 2007 on the “awkward urban site”, with construction being completed in Easter 2015.
Jane Duncan of the RIBA said: “The Murphy House is this year’s best example of how to overcome challenging constraints.”