Vinyl siding

Claim 1

In a building siding unit comprising a sheet having an upper portion having a plurality of spaced, horizontally elongated, aligned fastener receiving slots disposed therein, an interlock receiver channel disposed on said upper portion and spaced from said plurality of fastener receiving slots, the improvement comprising isolation means disposed in a U-shaped configuration partially around at least some of said aligned fastener receiving slots and in an area above said interlock receiver channel, said isolation means comprising vertical stress relief means at each side of at least some of said fastener receiving slots, said vertical stress relief means comprising a series of thin strips of said sheet and an elongated slot lying below corresponding ones of said fastener receiving slots and spanning the distance between said stress relief means, whereby said isolation means serves as a means to ameliorate the effects of expansion and contraction of said building siding unit caused by changing weather conditions.