As a task for the future of architecture, "building on" existing buildings - adding on, extending and rebuilding - has recently received more attention, especially in view of the impact on resources and the climate.

For several decades, w:a has been designing innovative concepts for the careful further development of existing buildings - from small-scale roof extensions to concrete refurbishments, removals and extensions in hybrid construction to large-scale projects such as the Grandhotel Astoria in Leipzig.