eaves vs mansard

eaves

noun
  • The underside of a roof that extends beyond the external walls of a building. 

  • Something that extends over or projects beyond. 

mansard

noun
  • The upper storey of a building, surrounded by such a roof 

  • A mansard roof 

adj
  • having two slopes on each side, the lower being steeper than the upper 

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