prefab vs slap together

prefab

verb
  • To prefabricate. 

adj
  • prefabricated 

noun
  • A single-storey prefabricated home built in many British cities immediately after World War II, intended to have a short life, but in a few cases still in use. 

  • A reusable object in a video game world. 

  • A prefabricated building. 

  • A prefabricated section of a building. 

slap together

verb
  • To put together hastily; to assemble carelessly and improvisationally. 

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