Abstract: A clamp having a clamp base that is attachable to a flat or sloped roof. A clamp top is releasably attachable to the clamp base. The clamp top includes a pedestal that is snap-fittingly engaged to the clamp base. The pedestal is made in two parts that are interconnected by an interconnecting wall that is releasably engaged by a locking member that forms a part of the clamp base. The header of a solar collector is confined in a space defined by the clamp base and clamp top. In a barrel tile application, a plurality of feet are attached to the bottom of the clamp base. At least one foot abuts the tile on opposite sides of a longitudinal axis of the tile. The bottom of each foot is contoured to match the convex surface of the tile. No feet are needed where the roof covering is flat.