Abstract: Roofing elements, particularly suitable for use on flat roof constructions, are provided with co-operating means on each of at least one pair of opposite side edges for co-operation with at least two adjacent elements on each of the side edges. When assembled, movement of any one element involves movement of at least one co-operating element on each of the opposite sides edges. Such bidirectional co-operation results in an interlocked roof construction wherein the uplifting of individual roofing elements by the action of the wind or other forces is substantially eliminated. Uplift pressure caused by wind passing over the roof surface can be further reduced by providing communicating air-flow passages between co-operating elements.

Abstract: A masonry block unit having spaced, selectively removable, vertical flanges on its inner face which are so spaced that they may be laid in the same direction and overlapped corresponding to the spacing in order that alternate flanges will provide a continuous row for attaching cladding and between such rows standard insulation may be placed, with the removal of the flanges which do not fall in the continuous lines.