ceiling vs roofing

ceiling

noun
  • The overhead closure of a room. 

  • The highest altitude at which an aircraft can safely maintain flight. 

  • The overhead interior surface that covers the upper limits of a room. 

  • The smallest integer greater than or equal to a given number. 

  • The upper limit of an object or action. 

  • The measurement of visible distance from ground or sea level to an overcast cloud cover; under a clear sky, the ceiling measurement is identified as "unlimited." 

  • The inner planking of a vessel. 

  • The maximum permitted level in a financial transaction. 

roofing

noun
  • A way of travel which consists in clambering over the roofs of skyscrapers. 

  • The process of constructing a roof or roofs. 

  • Material used on the outside of a roof, such as shingles. 

How often have the words ceiling and roofing occurred in a corpus of books? (source: Google Ngram Viewer )