Abstract: Rolled or extruded box beams and rafters are supported from an existing wall or other structure with the aid of added posts. The beams and rafters extend trasversely to each other, the rafters being secured at the wall by an anchor fascia. A front fascia is fixed to the rafters and also defines a gutter. Roof panels on the rafters are joined along their edges. Each roof panel has a shaped cup edge and an opposite shaped hook edge. The hook of one panel fits into the cup of the adjoining panel. A fastening flange on each cup edge affords means for fixing the panels to the rafters.Preferably the visible bottoms and sides of the rafters and the beams are covered by decorative sheaths, each being an open channel with means for attachment to the rafters and beams. The beams and related rafters are configured to approximate the nominal sizes of conventional wooden structural members, and the exterior surfaces of the fascia, sheaths and anchor fascia are finished in a wood pattern.