The invention is a rubber or plastic mat with four sidewalls for collecting the grease drippings from a conventional barbecue grill. This system and interface includes an open-topped bucket-well structure which is embedded in a foundation, and which is sized so as to permit the received base of an inserted column to be adjusted laterally, in a multidirectional sense, vertically angularly, and axially rotationally, and with substantial clearance, so as to enable easy correct positioning of a column. A sheath provided with a channel is pivotally mounted with respect to the hub and is positioned in an initial position in which the through opening in the protector is closed by the sheath.