Patent ID: 8850771

Claim:
A synthetic roofing element of a shingle or tile type comprising: (a) a headlap portion and a tab portion, each having top and bottom surfaces; (b) the headlap portion and the tab portion each extending between their respective top and bottom surfaces; (c) the headlap portion being adapted to have its top surface generally covered in the installed condition of the element on a roof, and the tab portion being adapted to have its top surface generally uncovered and weather-exposed in the installed condition of the element on a roof; (d) the element having a periphery defined by upper, lower, right and left edges with the right and left edges having generally straight, linear edge portions; (e) the element being essentially comprised of a relatively rigid construction; (f) at least one spacing projection disposed adjacent to said headlap portion on at least one of said generally straight, linear left and right edge portions; and (g) at least one stress relieving zone in the headlap portion disposed inside one of the generally straight, linear left and right edge portions of the element periphery and adjacent to said at least one spacing projection; (i) wherein at least a portion of the at least one stress relieving zone being comprised of a relatively flexible construction, relative to said relatively rigid construction; (ii) whereby said relatively flexible construction comprises means for relieving forces acting upon any of said left edge and right edges due to thermal expansion and contraction, and without breakage, when a plurality of said elements are installed side-by-side in fastened engagement with a roof; (h) wherein said at least one stress relieving zone includes means for expansion and contraction within the elastic limit of the material of which it is comprised and (i) each stress relieving zone being comprised of a plurality of perforations, with at least some of the plurality of the perforations being openings spaced entirely inside one of the generally straight, linear left and right edge portions of the element periphery, extending between and connecting top and bottom surfaces of the headlap portion, and with none of the stress relieving zones being in the tab portion of the roofing element.