joist vs stringpiece

joist

noun
  • A piece of timber or steel laid horizontally, or nearly so, to which the planks of the floor, or the laths or furring strips of a ceiling, are nailed. 

verb
  • To fit or furnish with joists. 

stringpiece

noun
  • A long piece of timber, forming a margin or edge of any piece of construction; especially one of the longitudinal pieces supporting a flight or run of stairs. 

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