Photos taken on August 24, 2015. Click on any picture for a larger version.
The condemned building appears to be the brick garage behind the house at 1337 E Mason. Per the 1936 Sanborn Map, this brick building was an “Auto Painting & Body Works” with a roof full of skylights.
The WI AHI has a listing for this brick garage (link below). Built around 1923, the building may be eligible for NRHP listing.