bressummer vs hammer beam

bressummer

noun
  • A large, horizontal supporting beam which bears the weight of a wall starting on a first or higher floor, particularly when exposed or used to support a jetty (timber-frame overhang construction). 

hammer beam

noun
  • A member of a kind of roof truss (a hammer-beam truss), so framed as not to have a tiebeam at the top of the wall. Each principal has two hammer beams, which occupy the situation, and to some extent serve the purpose, of a tiebeam. 

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