Cheswold, Dover, and Hartly were alerted this morning for a house fire on Omni Drive, off of West Denney's Road.  Command 43 arrived to find a one story house with smoke showing from the attic.  Dover Engine 6 arrived next and laid a supply line from West Denney's Road.  They began to stretch an attack line into the front door when Command 43 redirected them to a side door to avoid a collapsing chimney.  Cheswold engine 43-3 arrived and the crew was directed to take an attack line into the crawl space as fire had just been discovered there.  Firefighters were removed briefly from the first floor until the crawl space fire could be extinguished.  Hartly arrived and used their tanker to supply the operation and their crews helped with extinguishment.  The house required extensive overhaul.