An improved purlin clip has an arm and a leg defining a channel to receive the lower flange of a ceiling purlin. A pin is integrally formed with the lower leg of the clip and extends downwardly. The pin is adapted to penetrate a ceiling membrane. A cap is frictionally fit onto the pin to retain the membrane adjacent the purlin, and to support the membrane, with the insulation blown in between the membrane and the ceiling deck. The pin includes teeth or barbs for retentively engaging the cap.