Hip Roof
A hip roof is a rectangular roof that slopes on all four sides.
A regular hip has equal slopes on all sides while an irregular hip has different
slopes on the main roof and hip end roof. Easy Rafters does not calculate a complete
four sided hip roof, but rather calculates the common, hip, and jack rafters
for one end of a hip roof.
To Calculate a Hip Roof
Select Hip from the Roof Type dropdown list or click on the corresponding button on the toolbar to calculate a hip roof.
The preview window displays a dimensioned plan view of the hip roof.
Design Tab
Main Slope
Enter or select the slope of the main roof common rafter.
The slope of the hip end will update automatically to match the main roof slope.
Hip End Slope
To calculate an irregular hip enter or select the hip end slope after the main slope has been entered.
Building Width
Enter the total width of the building.
Main Overhang
Enter the horizontal overhang of the main roof common rafter including the fascia board.
End Overhang
This field is disabled for regualr hip roofs since the overhangs will always be equal.
For irregular roofs select "Equal" or "Not Equal" from the dropdown list.
Irregular hips will have unequal overhangs by default since the common and king common rafters
have different slopes. Making the overhangs equal involves offsetting the hip rafter along the
main or hip end wall plate and adjusting the height of the hip end wall to compensate for the
overhang difference.
Heel Height/Seat Cut
Accept the default heel height and seat cut dimensions calculated by Easy Rafters or
override the defaults by locking one or the other and entering the desired measurement.
Hip Correction
Select "Drop the Hip" or "Back the Hip" from the dropdown list.
Hip rafters must be dropped or backed so that the edges of the rafter won't interfere with the roof sheathing.
Dropping a hip lowers the heel of the hip rafters while backing a hip involves
beveling the top edges of the hip rafters.
Dropped hips for irregular hip roofs will be shifted slightly off their centerline to
compensate for the different amount of drop required for the main and hip end roofs.
Backed hips for irregular hip roofs will have different backing angles for the
main side and hip end side of the hip rafter.
Note: The hip shift or backing angles will be displayed in the hip rafter
top view on the Hip tab and in the deatil drawing on the Corner Detail tab.
Rafter Spacing
Select an on center spacing from the dropdown list.
The spacing is used to layout the jack rafters on the Layout tab.
Note: the spacing can also be changed on the Layout tab.
Lumber Sizes
Enter or select the lumber sizes for the common rafter, hip rafter, ridge board and fascia board.
The common rafter size is also used for the king common rafter and the jack rafters.
Enter a ridge thickness of zero or select "No Ridge/Purlin" if no ridge board is used.
Fascia Type
Select Plumb Cut or Square Cut from the dropdown list
(square cut is not available for irregular hip roofs).
Drawing Tabs
Common
The Common tab displays a dimensioned side view of the hip roof common rafter.
King Common
The King Common tab displays a dimensioned side view of the hip roof king common rafter.
Hip
The Hip tab displays a dimensioned side view and top view of the hip roof hip rafter.
Main Jacks
The Main Jacks tab displays a dimensioned side view and top view of the hip roof jack rafters
for the main side of the hip rafter on an irregular hip roof. The drawings are representative of all of the main side
jack rafters and do not include the overall lengths which are available on the Layout tab.
Hip End Jacks
The Hip End Jacks tab displays a dimensioned side view and top view of the hip roof jack rafters
for the hip end side of the hip rafter on an irregular hip roof. The drawings are representative of all of the hip end side
jack rafters and do not include the overall lengths which are available on the Layout tab.
Layout
The Layout tab displays a plan view of the hip roof showing the
layout and lengths of the jack rafters. The layout toolbar appears below the main toolbar
when the Layout tab is selected and contains options that affect the layout
of the main roof jack rafters.
Note: the hip end jack rafters are always laid out on center
from the king common rafter.
Spacing
Select an on center spacing for all of the jack rafters from the dropdown list.
Main Roof Last Common
Enter the distance from the center of the last main roof common rafter
to the center of the longest main roof jack rafter. This field is disabled
when "Centered At Peak" is checked.
Centered at Peak
Check this box to layout the main roof jack rafters on center
from the point of the hip roof and uncheck this box to layout the main roof jack rafters
using the "Main Roof Last Common" measurement.
When this option is checked the main roof jack rafters will line up
with the hip end jack rafters, but may not be on center with
the main roof common rafters.
Include Overhang in Jack Lengths
Check this box to include the overhang in the jack length measurements and
uncheck the box to not include the overhang in the jack rafter lengths.
When this option is unchecked you can leave the jack rafter tails long,
snap a chalk line, and cut the tails after installation ensuring
that the fascia board is perfectly straight.
Sheathing
The Sheathing tab displays a plan view of the corner of the main roof and the hip end roof
viewed at an angle perpedicular to the plane of the roof and showing all dimensions and angles
necessary to calculate and cut the required sheathing.
If the length of the common rafter or king common rafter is longer that the
width of a single piece of sheathing it also displays dimensions for a
section equal to the width of a standard piece of sheathing (48" imperial, 1220 mm metric).
Corner Detail
The Corner Detail tab displays a detail drawing in plan view of one corner
of a hip roof showing any hip shift, hip offset and wall height difference.