roof vs roofing

roof

noun
  • The top external level of a building. 

  • The external covering at the top of a building. 

  • The upper part of a cavity. 

  • An overhanging rock wall. 

  • The surface or bed of rock immediately overlying a bed of coal or a flat vein. 

verb
  • To cover or furnish with a roof. 

  • To traverse buildings by walking or climbing across their roofs. 

  • To put into prison, to bird. 

  • To shelter as if under a roof. 

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 roof and roofing occurred in a corpus of books? (source: Google Ngram Viewer )