The Enhanced Irregular 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:
[Prefs]Irregular Jack Spacing setting, either On-Centers or Mating. See illustrations, below, for more explanation.
Also, if an Irregular Pitch is stored, then subsequent presses of the
[IrJack] key will switch between Irregular and Regular Jack Rafter
results. If no Irregular Pitch is stored, the IrJack key will
function the same as the [Jack] key
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 for an Irregular hip
roof - the Minor Pitch is 9"/12".
Input
9
[Inches] [Hip/V]
Display
see results, below
Part C: Jack Rafter Layout.
Input
[Conv]
[IrJack]
Display
see results, below
Scroll down to see all of the results. Where are the regular jack
rafter layout dimensions? Tap [Done] and then tap [Jack] to see
them. Repeated taps of [Jack] switch between Irregular and
Regular Jack Rafter Layout display.
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