weather strip vs weatherstrip

weather strip

noun
  • A strip of wood, rubber, or other material applied to an outer door or window so as to cover the joint made by it with the sill, casings, or threshold, in order to exclude rain, snow, cold air, etc. 

weatherstrip

noun
  • A narrow piece of material used to prevent cold air from entering a building through the edge of a window or a door. 

verb
  • To apply such a strip. 

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