Take a look at this adaptive reuse of a Pigsty! The building was originally built in 1780 and used as a pigsty (Saustal in German) for most of its life. The structure was partially destroyed during the Second World War and was only reassembled for minor use in the period since the war. The building owner wanted to convert the building into a showroom, but the condition of the building made a renovation hard to finance as an upgrade.
The solution proposed by design firm FNP Architekten from Stuttgart was to place a "house within a house." A wood framed inner house was built and inserted into the structure. The new insert does not however touch the facade yet at the same time it protects the old pigsty by sheltering it under its roof canopy and preventing collapse. The windows of the insert are placed in the same locations as that of the original pigsty which oddly enough imbue significance to a modern arrangement of windows on the facade. The apertures you see were originally placed for use by the farmer and pigs in their daily routines.
The results are striking and make a wonderful statement about the embodied historic, economic, and material energy present in older structures. If an eighteenth century pigsty can be renovated to such a delightful end, imagine all of the older historic structures that exist in American inner cities that languish at ineptitude of our civic leaders to provide incentives for their redevelopment. Surely a building that can leverage the embodied energy of three hundred years is worth more to a city and a developer than a newly conceived structure reliant on its own internal architectural / programmatic dialogue to give it meaning and depth.