Basic
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Layout of the Common Rafters, End Common Rafters and Hip Rafters
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Layout of the Common Rafters, End Common Rafters and Hip Rafters
The layout of the common
rafters for
a hip roof is the same as the layout for a gable roof. See "How To
Frame Gable Roofs". Mark the rafter plumb lines with a 150
unit of rise and 250 unit of run. Snap a chalkline at 1/3 of
the rafter
depth to locate the seat cut of the birdsmouth. Accommodate
the ridge at the top end of
the rafter by measuring back 1/2 the thickness of the ridge (10 mm) at
90 degrees to the plumb line. Mark a new cutting line.
The end common is adjusted to 1/2 the thickness of the common rafter measured at 90 degrees to the plumb line. See figure 3 bottom.
Layout the hip rafter by marking a 150/353.6 plumb line at the upper end of the rafter. See figure 3. Continue the plumb line square along the top edge of the hip rafter and mark the centre of the line as working point 1. Measure a distance down the hip rafter equal to its line length and establish working point 2. Measure a distance down the rafter equal to the length of the overhang and mark the location of the plumb cut.
The end common is adjusted to 1/2 the thickness of the common rafter measured at 90 degrees to the plumb line. See figure 3 bottom.
Layout the hip rafter by marking a 150/353.6 plumb line at the upper end of the rafter. See figure 3. Continue the plumb line square along the top edge of the hip rafter and mark the centre of the line as working point 1. Measure a distance down the hip rafter equal to its line length and establish working point 2. Measure a distance down the rafter equal to the length of the overhang and mark the location of the plumb cut.
