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Butler Folded Plate Greenhouse Roof

FOLDED plate structures have been used for centuries, generally to enhance the aesthetics of a building but also because of some inherent structural characteristics. There are many possible folded plate configurations with most categorized according to fold type, arrangement and resulting cross section. Concern for water removal from large area greenhouse roofs led R. G. Butler of Westboro, MA, to propose a folded plate roof constructed of triangular plates in a parallel fold arrangement to create an M cross section (Fig. la). He constructed a model of the roof using flat acrylic triangles as plates tilted at 45 deg with the horizontal. The sloping valleys were parallel to the building sides. The ridges were horizontal and at an angle to the sides. This paper discusses (a) the design, testing and structural evaluation of a folded plate roof model based on the Butler roof and (b) design, fabrication and erection of a 7.3 m x 7.3 m (24 ft x 24 ft) Butler roof greenhouse.