'the roof. the roof, the roof is in fire' can be traced back to a chant called at funk gigs and early discos in the 70's. It is probaly most associated with Parliament and Funkadelic but fans of the Gap Band also used to chant it.
It was just generally associated with gigs and club nights when the atmosphere was so hot that the crowd would chant "the roof etc..."
Anyway after all this Rock Master Scott and the Dynamic 3 did the classic party jam called "The Roof is on fire" in 1984.
As Shourisha says, if its the one that goes "The roof, the roof, the roof is on fire, Burn MotherF####er Burn!" it is the Bloodhound Gang - a mighty rocking tune too!!