The Enhanced Jack Rafter Layout Function provides the following layout
information for hip roofs beyond the information provided by the [Hip/V] (Hip / Valley Rafters) Function - with the minimum amount of hassle for you.
Incremental change in Jack Rafter Lengths
Lengths of each Jack Rafter
Plumb Cut Angle
Level Cut Angle
Cheek Cut Angle
Information required for this function includes:
Two of the following values to describe the Regular Common Rafter geometry:
Also, if an Irregular Pitch is stored in [IrPitch] then subsequent presses of the [Jack] key will switch between Irregular and Regular Jack Rafter results.
In addition to [IrPitch], calculations for Irregular Jack Rafters are based upon if the [Prefs]Irregular Jack Spacing is set to either On-Centers or Mating. The next two illustrations help explain the difference.
Irregular Hip/Valley layout with Rafters mating at the hip/valley.
Irregular Hip/Valley layout with rafters spaced at the on-center distance.
Part A. Common Rafter Length and cut angles.
Input
[clr]
[clr]
12 [Feet] [Run]
7 [Inch] 1 [ / ] 2 [Pitch]
[ Diag ]
[ Diag ]
Display
0
Run
12ft
Pitch
7- 1/2in/12in
Diagonal
14ft 1- 13/16in
see results, below
Part B: Hip/Valley rafter length and cut angles.
Input
[ Hip/V ]
Display
see results, below
Part C: Jack Rafter Layout.
Input
[ Jack ]
Display
see results, below
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