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

Abstract

A sub-rafter configured to substantially conform to a roof that is curved between an eave and a ridge. The sub-rafter comprises a bottom flange, a top wall, 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. The slot comprises a lower end positioned in the web and spaced a predetermined distance from the bottom flange. A top band may be joined to the top wall after the sub-rafter is joined to existing structural members. A roofing system of the present disclosure comprises: a sub-rafter attached to a structural member of an existing curved roof, a top band joined to a top wall of the sub-rafter, a cross-member joined to the sub-rafter, and a new roof structure attached to the cross-member. In embodiments, the new roof structure comprises metal panels.

What is claimed is: 
     
         1 . A sub-rafter configured for installation on a roof of a building, the roof being at least partially curved between an eave and a ridge, the sub-rafter comprising:
 a bottom flange;   a top wall spaced from the bottom flange;   a web disposed between the bottom flange and the top wall;   a slot extending through the top wall and at least partially through the web toward the bottom flange, wherein a closed end of the slot is spaced from the bottom flange; and   the bottom flange being conformable to a shape of the roof between the eave and the ridge.   
     
     
         2 . The sub-rafter of  claim 1 , wherein at least one of the bottom flange and the top wall is planar when the sub-rafter is in an initial state and is generally linear, and wherein at least one of the bottom flange and the top wall is not planar when the sub-rafter is in a second state that is not linear. 
     
     
         3 . The sub-rafter of  claim 1 , wherein the top wall is approximately parallel to the bottom flange when the sub-rafter is in the initial state, and wherein the top wall is not parallel to the bottom flange when the sub-rafter is in the second state. 
     
     
         4 . The sub-rafter of  claim 1 , wherein the web is oriented approximately perpendicular to one or more of the top wall and the bottom flange. 
     
     
         5 . The sub-rafter of  claim 1 , wherein:
 the web is a first web that extends from a first long edge of the top wall; and   the bottom flange is a first bottom flange that extends from the first web; and   wherein the sub-rafter further comprises:
 a second web extending from a second long edge of the top wall, wherein the slot at least partially extends into each of the first and second webs; 
 a second bottom flange that extends from the second web, and 
   the second bottom flange being conformable to the curvature of the roof between the eave and the ridge.   
     
     
         6 . The sub-rafter of  claim 1 , wherein the closed end of the slot is rounded and has a diameter that is greater than a width of the slot when the sub-rafter is in an initial state. 
     
     
         7 . The sub-rafter of  claim 1 , wherein the sub-rafter comprises a metallic material with a substantially uniform thickness or a composite material comprising carbon fiber with a substantially uniform thickness. 
     
     
         8 . The sub-rafter of  claim 1 , wherein the slot is oriented approximately perpendicular to a reference plane defined by the top wall when the sub-rafter is in an initial state. 
     
     
         9 . The sub-rafter of  claim 1 , further comprising a top band affixable to the top wall after the sub-rafter is bent and the sub-rafter is in the second state. 
     
     
         10 . The sub-rafter of  claim 9 , wherein the top band extends from a first portion of the top wall on a first side of the slot, across the slot, and to a second portion of the top wall on a second side of the slot. 
     
     
         11 . The sub-rafter of  claim 10 , wherein the top band is affixed to the top wall with:
 a first fastener that extends through the top band and the first portion of the top wall; and   a second fastener that extends through the top band and the second portion of the top wall.   
     
     
         12 . The sub-rafter of  claim 9 , wherein the top band is formed of a metallic material or a composite material, wherein the top band has a first thickness that is substantially uniform and equal to or greater than a second thickness of the top wall. 
     
     
         13 . The sub-rafter of  claim 1 , further comprising a first length measured along the top wall when the sub-rafter is in the initial state, and wherein the top band has a second length that extends across at least a majority of the first length. 
     
     
         14 . 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. 
   
     
     
         15 . The roofing system of  claim 14 , wherein the cross-member is aligned vertically with the structural member of the roof and is oriented approximately perpendicular to the sub-rafter. 
     
     
         16 . The roofing system of  claim 15 , further comprising a second cross-member positioned on the top band and attached to the sub-rafter, the second cross-member oriented approximately parallel to the first cross-member, wherein the second cross-member is positioned between two structural members. 
     
     
         17 . The roofing system of  claim 14 , wherein a closed lower-end of the slot is generally circular. 
     
     
         18 . The roofing system of  claim 17 , wherein:
 a lower portion of the slot proximate to the closed lower-end has a first width measured between two linear edges of the slot, and   an upper portion of the slot proximate to the top wall has a second width measured between the two linear edges of the slot, the second width being greater than the first width.   
     
     
         19 . 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. 
   
     
     
         20 . The method of  claim 19 , wherein the structural sheet material comprises at least one of a metal, a composite material, and a plastic.