Jack Rafter Lengths

Jack Rafter Spacing
Enter the jack rafter on center spacing. Jack Rafter lengths are calculated from the hip rafter seat corner of the building.

Jack Rafter Material Thickness
Enter the width of the jack rafters.

Special Jack Rafter Plate Line Run
Optional, enter the run along the eave line for any special jack rafter layout.

Calculated Results

Jack Rafter Shiften
Use this dimension to layout the shifted plumb line at the peak of the jack rafter.

Main Jack Rafter Length Difference
The differene in length of each jack rafter.

Main Special Jack Rafter PL Run
The differene in length of each jack rafter.

Main Special Jack Rafter Length
The length of the jack rafter, to the long point of the Jack Rafter.

Main Side HR Layout First Jack Rafter
Dimension from the hip rafter plumb line on the unbacked hip rafter to the layout mark for the first jack rafter. This dimension is to the uphill side of the jack rafter.

Hip Rafter Layout Jack Rafter Difference
The differene in length for the hip rafter layout marks to locate each jack rafter on the side of the hip rafter.