The attic of a nineteenth-century apartment building protected under historic-preservation ordinances was remodelled and linked to the apartment below – nestled, as well, within a mansard roof – by a single flight of stairs. During the construction phase the entire roof was insulated, including the existing apartment. The challenge was to make an airy, functional space out of the dark attic with its low, slanted ceilings, and at the same time, to fulfil the requirements specified by historic preservation. Large cuts into the roof were not permitted. The architects created a bright, loft-like space in which the original wood structure is still partially visible. The bathroom and the storeroom are cleverly hidden in black, light-frame structures.