Roof 2100

Vienna's summers are projected to run 27 to 33°C by 2100, with tropical nights that no longer let a building cool down. The site is an uninsulated Gemeindebau attic that already fails twice over, trapping heat in summer and losing it in winter. The proposal is a double roof, clay thermal mass over a ventilated cavity that vents by stack effect in summer and closes for insulation in winter, with a straw-insulated timber partition running the depth of the attic that folds open into a semi-outdoor room. Existing beams are reused, and the new materials are reclaimed brick, rammed earth and an acoustic panel made from Japanese knotweed and Wiener Tegel, the loam Vienna digs out for its metro extension.