Harcombe is a minimalist residence located in London, England, designed by Forrester Architects. As a modern interpretation of the traditional London Roof the butterfly form provides a unique language for a desirable rear house extension. Avoiding the mundane typical rear extension the roof form is expressed internally as exposed timber joists. This provides a dynamic architectural feature and adds a natural warmth to the new space. The new roof construction known as a warm roof construction avoids the traditional cold roof construction to provide a highly efficient thermally insulated roof construction.