Abstract: A panel construction for roofs and walls of buildings incorporates holding clips secured to supporting roof purlins in overlying relation to locator strips which are installed preliminarily to establish the spacing of the clips. After the locating strips are positioned, the clips are temporarily located by interfitting portions of the strips and clips, whereafter permanent fasteners are extended through the clips and strips and into the supporting structural element. The clips are double bent sheet metal elements having integral latch-type retaining portions. The panels, of sheet material, have hollow upstanding dovetailed latching ribs extending longitudinally of medial areas thereof, and complemental partial latching rib portions along their longitudinal edges and which interlock in sealed engagement with the complemental partial rib portions of adjacent panels to define dovetailed latching ribs at the joints of the adjoining panels.