Sub-rafter with vertical slots and roof system for a curved roof

A roofing system affixed to an existing roof that is curved between an eave and a ridge or peak, comprising:

• a curvable sub-rafter disposed over an exterior surface of the existing roof and being attached to an existing structural member, the sub-rafter extending between the eave and the ridge and oriented approximately perpendicular to the structural member, wherein the sub-rafter comprises:
• a bottom flange;
• a top wall spaced from the bottom flange;
• a web extending between the bottom flange and the top wall;
• and
• a slot extending through the top wall and at least partially into the web;
• a top band fastened to the top wall, wherein:
• the bottom flange is conformable to a curvature of the roof between the eave and the ridge,
• a first mechanical fastener extends through the top band and through a first portion of the top wall on a first side of the slot;
• and
• a second mechanical fastener extends through the top band and through a second portion of the top wall on second side of the slot such that the top band bridges the slot;
• a cross-member positioned on the top band and attached to the curvable sub-rafter;
• and
• a new roof structure attached to the cross-member.

A method of forming a sub-rafter, comprising:

• providing a structural sheet material that extends along a longitudinal axis;
• forming at least two slots in the structural sheet material, the slots spaced along the longitudinal axis and oriented approximately perpendicular to the longitudinal axis;
• cutting the structural sheet material to a predetermined length;
• and
• folding the structural sheet material along three lines approximately parallel to the longitudinal axis to form the sub-rafter, wherein the curvable sub-rafter comprises:
• a bottom flange;
• a top wall;
• a web extending from the bottom flange to the top wall;
• and
• the slots extending through the top wall and at least partially through the web toward the bottom flange, wherein a closed end of each slot is spaced from the bottom flange.