Structural surface metal shingle covering

Claim 1

In a roof structure having a plurality of horizontal boards providing a supporting surface, a plurality of horizontally arranged courses of formed metal shingle elements each having a shingle wall of trapezoidal shape and generally planar, downturned tapering side flanges on said wall, a downturned bottom butt flange on said wall having a bottom edge adapted to contact corresponding walls of the next lower course of shingle elements; a plurality of flashing strip elements extending beneath and between edges of adjacent shingle elements of a course and positioned by said butt flanges; and means securing said shingle elements to said supporting surface; each shingle wall having a lower portion having a planar uninterrupted surface exposed to weather and an upper portion covered by the lower portion of the next above adjacent shingle elements and associated flashing elements in the next above course of shingle elements; wherein the improvement comprises: means for minimizing lateral and longitudinal distortion of each shingle wall out of its normal preformed plane at the contact zone of the butt flange edges of shingle elements of the next above course, said distortion minimizing means comprising indentation means extending laterally and longitudinally in the upper portion of each shingle wall above the contact of the butt wall of the upper shingle therewith and spaced from the side flanges thereof; said means for securing each shingle element being located in the portion of said shingle wall between said indentation means, said side flanges and above said butt wall contact of the upper shingle with the lower portion whereby said planar surface of the lower portion and edge of the butt wall of the upper shingle form a virtually uniform joint line appearance.