paving vs subfloor

paving

noun
  • The hard durable surface placed directly atop the ground, as on a street or sidewalk. 

  • Interior pavement, as in a cathedral. 

adj
  • Pertaining to the material used for pavement, or to the surface itself. 

subfloor

noun
  • The floor structure supporting and underlying the visible flooring or other finishing surface such as a carpet 

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