Hip Roof Framing Plans — Designs and Illustrations
Standard Hip Roof Framing Plans
6x12 Pitch Hip Framing Plan 7x12 Pitch Hip Framing Plan
8x12 Pitch Hip Framing Plan
Design work available in PDF & DWG file format
How to build a hip roof & Hip Roof framing plans
Equal pitch hip roof framing plans showing basic hip framing layour and placement of common rafters and hip roof rafters by custom house plan designer.
In this article we will try to show you how to build a simple "hip roof" and try and show the component parts that make up a "equal pitch hip roof" structure using the "double cheek cut hip rafter method" used by most framers today.
In this method of construction the center ridge board will grow by half the thickness of the ridge board material, usually 3/4" at each end of the structure.
In this example we are looking down on the right rear corner of a simple rectangular building. Using half the span distance of the building less half the ridge board thickness which is 3/4" in this example mark your top plate and set ahead 1 1/2". That will be the location of the first common rafter front and rear on both ends of the building. Your jack rafters will start from that position and layout on 16" centers toward the right rear corner. This is the hip and jack rafter measurements as shown in this example. You could actually cut all four hip sections from these measurements and they would complete your rafter construction perfectly.
But that would not work well for ceiling joist layout and being able to tie both rafters (common and Jacks) together to create a solid and well built home. So we would want to offset the common and jack rafters 1 1/2" to allow both to be able to lap beside each other and be nailed together forming a well built roof system.
This method will cause all of the rafters and jack rafters on the front side to maintain a 16" on center balance. This makes cutting the roof sheathing much easier and quicker. In the event the ceiling joist are used as a attic flooring your plywood sheathing will work well also.
Note: This will force you to custom cut the front right corner as well as the front and rear sections on the left end of the building. I show this in figure #4 marked "Special Cut Jack Rafter Layout" near the bottom of the page.
Not to worry though its easy to do. The right front section jacks would simply be 1 1/2" shorter. The left end can be simply measured once your layout work is complete maintaining your 16" on center the entire width of the building. The remaining jack rafters in these two sections would simply decrease each one by a given number according to the roof pitch used.
Roof Terms commonly used in residential construction:
2006 IRC building Code in relation to cutting and notching Rafters & Ceiling Joist:
R802.6 Bearing:
"The ends of each rafter or ceiling joist shall have not less than 1 1/2" (38mm) of
bearing on wood or metal and not less than 3 inches (76mm) on masonry or concrete".
R802.7.1 Sawn Lumber: "
Notches at the ends of the member shall not exceed one-fourth the depth of the member".
Regular Pitch Roof: This term is used meaning the ridge board is always found in the center of the structure and the rafters on each side are the same identical length and design. In this type of hip roof for example the hip rafter is set on exactly 45% from the outside corner and is therefore called a regular pitch hip roof. A gable roof would also be called a regular pitch roof building as well.
Irregular Pitch Roof:
This roof type would be considered unequal or irregular because one surface of the
building such as the front and rear sides might be on a lower slop or pitch than the
right and left sides causing the center common rafter, the hip rafter and all jack
rafters on the right and left sides only to be of a different angle and the top plumb
cut would be different. The hip rafter would not be on a 45% angle either.
Most construction calculators can give you the diagonal length of a irregular hip
rafter from the exact corner of the building but allows for no overhang at all. If you
want to have overhang the hip overhang would have to be shortened on the irregular side
so the overhang elevation will be at the same height but the overhang distance would be
much less making the roof in this builders mind look badly.
Equal Overhang: In the irregular pitch hip roof structure described above the over hang distance and elevation can be the exact same by simply moving the seat of the hip rafter toward the irregular side of the building a distance determined by the two pitch angles.
Double Cheek Cut Method: In this method of framing a hip roof the Hip Rafter will have a cheek cut on both sides as it will fit between the first common rafter on the front and back and the center common rafter on the hip end of the structure. On the hip end there will only be one common rafter that fits perfectly against the end of the ridge board making a perfect hip structure. In this method of building this causes the center ridge board to grow in length from one hip end to the other by half the thickness of the ridge board material used, usually 3/4". In this builders experience this type or method of framing is the best and certainly the easiest to use. Once you set the first common rafters front and rear you can then set a common rafter at the opposite end of the ridge board length so you can install the ridge board itself. Once this is done you would set the one single common rafter on the hip end and your set to start the hip corners or do the same at the other end of the building. Once both hips sections are complete you can then fill in all the remaining common rafters.
Rafter Seat: This would be the notch you cut in the bottom of the rafter which sets on top of the outer most wall of your structure. In determining the seat cut you would use no more than 25% of the rafter material depth.
Birds Mouth: This is the same as the Rafter Seat above but called by another name by many carpenters.
HAP: "Height Above Plate" or commonly known as the plumb line which extends vertically form the seat cut vertically upward to the top of the rafter material on the plane or pitch desired.
Rafter Pitch: This would be the angle in degrees the roof rafter climbs in a 12" distance. Rafter pitch can run for standard asphalt shingles from 3 1/2 to as high as you might want. In most cases contractors would use a 4x12 pitch meaning that for every 1' the rise would be 4". So a run of 12' the rise would be 48" high.
Rafter Angle: This would be the same as the Rafter Pitch above but identified in degree's.
Building Span: The entire depth of the building from outside wall sheathing to outside wall sheathing.
Building Ridge Board: The ridge board is located in the center of the building and each common rafter would rest against it. Code calls for a minimum of 1" and must be as high or better than the angle cut on the top of each common rafter. 1 1/2" x 10" would be the most common size but can be larger in both height and thickness. When using a very high pitch roof you might want to use a 1 3/4" x 11 7/8" LVL ridge board to extend well below the bottom of the rafter.
Building Run: The building run is equal to half the building span minus the building ridge board thickness. A simple example would be a building structure span of 24' deep divided in half and less 1/2 the ridge board thickness of 1 1/2' giving you a run length of 11'-11 1/4".
Roof Rise: The roof rise is the vertical distance the roof pitch creates by calculating the run by the roof pitch. This however is not the top of the ridge board. To obtain that vertical distance you would need to add the rise plus the HAP together to get a total rise figure. The HAP or plumb line will be different for different roof pitches and for different materials.
Gable Roof: A gable roof has only two sides, causing each end to rise upward to the center point and on a regular pitch roof having both sides equal.
Hip Roof: Hip roofs will typically have four sides sloping upward to the center point. The regular hip roof will have four hip corners all connecting at the ridge line.
Shed Roof: Shed roofs often connect to another body and slop in one direction and has only one side.
First Common/King Rafter: This rafter along with the hip end common rafter create the hip end and are erected first on each hip end before the hip rafters are installed. This rafter is the same as the standard common rafter used on regular gable roofs.
Hip Rafter: The hip rafter is the corner rafter and is at a lower pitch angle than the common rafters and is typically set on a 45% angle from the corner.
Jack Rafter: Jack Rafters are on the same pitch as the common rafters on a regular pitch hip roof and are shortened each time it is set continuing the roof plane to the corner.
Building Overhang: The overhand may extend the distance needed to protect the main body of the structure and can be measured horizontally from the sheathing to the outermost part, usually including the Fascia board.
Rough Fascia: This is usually a 2x4 or 2x6 nailed at the ends of each rafter and used to strengthen the overhang system.
Fascia Board: This board is use as a finish material and nailed to the rough fascia board at the ends of the rafters or trusses and is also used as finish boards on the gable ends of gable roof type structures.
Shingle Strip: Usually a 3/4'x 2" wood strip nailed directly over the fascia board.
Freeze Board: The freeze board is nailed at the top of the outside wall directly underneath the soffit board and usually has a decorative moulding applied over it.
Barge Rafter: The barge rafter or hanging rafter is applied under the roof sheathing after it is installed and trimmed for the overhang desired. It can be supported by several methods and usually has the fascia board and shingle strip applied to it. Or it may be used to apply a vinyl covering directly to it.
Hanging Rafter: See Barge Rafter
Soffit Board: The soffit board is applied under the boxing overhang and has a continuous soffit venting system in it or may be a one peace venting vinyl material.
Continuous Ridge Vent: The ridge vent is usually applied over the standard roof shingles and can be aluminum or plastic with roofing shingles applied to it. Its purpose is vitally important as it is used to allow hot hair to escape cooling the attic area.
Continuous Soffit Vent: The soffit vent is vitally important as well as the ridge vent and work together to allow cooling of the attic area in warmer areas. Without proper ventilation the attic will collect moisture and cause mold and mildew damage.
Gable Louver: The gable louver is placed in the top of the gable end under the overhang to provide proper ventilation of the attic area.
Common Rafters
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Common rafters are the same on gable roofs as well as on hip roofs and
can be figured exactly the same way.
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Hip Corners
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Regular pitch hip roofs means that all four sides are on the same
angle plane and will run at a 45 degree angle directly from the
corner to the end of the center ridge board.
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Hip Rafters
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Hip roof rafters are designed with a lower pitch so the corner can be
made and roof sheathing can be applied to form the corner of
the structure properly. It also carries the smaller jack rafters.
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Plan View
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Our plan detail drawing shows all four corners of this simple hip
roof structure with all common rafters, hips and jack rafters
fitting together properly.
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Equal pitch roof Rafter layout
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Placing the ridge and common rafters should be the first thing to be laid
out on your wall top plates. From this layout you can mark out all the rest
of the common and jack rafter positions. It might be a good idea to draw a
big X where the rafters will actually set.
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Hip Rafter Side Cut Angles
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This side cut angle can be obtained the same way as the jack rafter
cheek cut angle.
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Jack Rafter Side Cut Angles
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Side cut angles or commonly called cheek cuts enable the jack rafter
to connect properly with the side of the hip rafter.
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Plywood Cut Angles
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Even though a equal pitch hip roof has hips running inward at a
45 degree angle the plywood sheathing cut angle is very different
and on our 4x12 pitch roof example it turns out to be 46.53 degrees.
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Jack Rafters
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Jack rafters start with the first common rafter and continue on to
make up the complete corner. These must be calculated properly to
fit in order for the sheathing to continue to the corner. When installing
your jack rafters be sure to straighten the hip rafter and install the
first two jack rafters some where in the middle to secure the hip. When
you install one side install the other side of the hip as well. This
will help keep the hip rafter nice and straight.
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Plans showing 16" centers for all rafters and ceiling joist.
Ceiling Joist Typical Layout
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Ceiling joist layout if placed properly will enable you to set all rafters
much quicker and finish with a very neat project.
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Special Cut Jack Rafter Layout
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In our example method of keeping all rafters and jack rafters on 16" centers
it will force you to custom cut three sections of these jack rafters. In
this example image I have marked them in light blue.
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Special Cut Jack Rafter Lengths
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These lengths can be determined once the layout work is completed.
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Irregular Pitch Hip Roofs
w/Equal Overhangs
Unequal pitch hip roofs are more complicated to design and used today on larger homes where attic space is needed. Unequal pitch roofs are hard enough to design and when you add equal overhang you have really kicked it up a notch. To make the overhang come out equal to the regular pitch side which is usually the front and back hip you simply have to raise the irregular hip roof side to match. Problem is that this is not always an easy thing to figure out.
When you rotate the irregular hip rafter around all the measurements you would be given by your calculator will not be right. This will cause the jack rafters to be set out of square with the rest of the common rafters causing your plywood or sheathing cuts to be out of square also. This can be time consuming on the actual job site trying to re cut sheathing to fit the jack rafters properly.
Calculators simply will not take this into consideration as they are designed to function on a center point to point basis or from the actual corner itself allowing for no overhang at all. If you use this method then you will have to custom cut each peace of sheathing to fit your jack rafters or cut back on your overhang distance making the home out of proportion all together. Or measure for and custom cut every jack rafter which is time consuming to say the least.
Irregular Hip Figure #1
Figure #1 shows us the low slop side and sets the dimensions for the overhang elevation and the Ridge elevation which must be maintained.
Irregular Hip Figure #2
Figure #2 shows us how much to raise the irregular side to align the equal overhang. This is accomplished by simply raising the rafter seat by the required amount using whatever method you like. It can be accomplished by simply ripping small blocking to set the irregular rafter on. The ceiling joist is still located in the normal place maintaining proper ceiling height but should be extended out over the top wall plate so as to add needed strength to the roof system.
Irregular Hip Figure #3
Irregular Hip Figure #4
Irregular Hip Figure #5
Irregular Hip Figure #6
All images and designs are owned by Vance Hester Designs and copyrighted 2008-2009. No material may be reproduced or republished for any reason anywhere without written permission.