Abstract: An adapter for use with a base curb for matching selected roof-top equipment to the curb without any field modification so that when the roof-top equipment needs of the building become known the adapter and roof-top unit may be installed. This eliminates roof integrity and leakage problems. The adapter is a substantially box member having a base positionable upon the roof curb and having an open frame positioned above the base. Inclined surfaces interconnect the base with the open frame. Channel members beneath the inclined surfaces add further rigidity to the adapter. The interior portions of the adapter include insulation so that condensation problems are eliminated.