Abstract: A staircase of monocoque construction comprises a pair of stringers, a series of successive and alternating treads and risers and nosings which are all made of solid wood or of composite wood such as O.S.B., pyrock, plywood, particle board, etc. At locations where these various components are to be joined, the components define facing grooves with a tapered space being also defined between the components. A gap filling substance, such as a polyester resin reinforced with micro-glass fibers, injected in the large ends of the tapered spaces fills the grooves as well as the tapered spaces and adhesively joins when it hardens the treads and risers one to another in succession, and also adhesively joins the stringers and the nosings to the treads and risers. The hardened resin "welds" the wooden components one to another thereby acting as a welded mechanical key, whereby the assembled structure forms a monocoque staircase. A method is also suggested to produce a monocoque staircase.