4. Covering residual spaces

Existing buildings often have residual spaces, such as patios or courtyards, left open to the sky. The scarcity of available surface areas and the frequent impossibility of extending buildings with additional additions (extensions and/or elevations) lead designers to imagine clever uses for these surfaces. Unlike underpinning or digging additional basements, which are very costly to implement, it's easier to create new surfaces by covering residual spaces with glass roofs. Installing these covers is an operation of varying difficulty, depending on the structure of the existing building. Its ancestor is undoubtedly the Parisian covered passage, a typical exercise in 19th-century architecture that provides light and protection from the elements. Hotel patios, office building lobbies, railway stations, museums... examples of these interventions are legion. Some of the most famous are for museums:...