Sometimes signs can be too large:
http://digitallibrary.usc.edu/assets...T-BUI-125?v=hr
"Apex Steel Corporation has completed one of the largest signposts atop a building to be erected in Los Angeles. The frame weighs more than 30 tons and is set on the Hancock Building, Wilshire Boulevard. Display area is 40 by 85 feet and was designed by Cejay Parsons, architect." -- Examiner clipping attached to verso, dated 10 May 1959.