1920s+1930s 1920’s-1930’s : Heating systems 1920s+1930s 1920’s-1930’s : Floors 1920s+1930s 1920’s-1930’s : Doors + Windows 1920s+1930s 1920’s-1930’s : Walls 1920s+1930s 1920’s-1930s : Roofs 1920s+1930s 1920’s-1930’s : Houses + Flats