Homebuilding Information and Planning

How To Frame A Hip Roof

One of the two most popular roof designs, if not the most
popular is the hip roof. Not only does it add architectural
lines to the design of a house, but it also offers more
protection from the elements to walls, windows, and doors,
when framed with a generous overhang. It also lends more to
the structural integrity of a home with its rafters tying
off to all four corners and walls of the structure.

Learning how to frame a hip roof is a little more complex than a gable roof. Besides a ridge board, a gable roof has only common rafters (all rafters the same length) as its only
components. The components of a hip roof are the ridge
board, common rafters, hip rafters, and jack rafters. The
hip roof does not always have a ridge board. If the building
is a square with all four walls being the same length, there
will be no ridge and the roof will resemble a pyramid.

When cutting the common, hip and jack rafters, their lengths
can be determined by using a calculator or a rafter table
book like "The Full Length Rafter Framer". The length of
the ridge can be determined by subtracting the width of the
building from its length. For example, if the building is 30
x 24, the ridge will be 6 feet in length. If the ridge board
is 1 1/2" thick (which is usually the case), then 1 1/2"
needs to be added to the ridge length. This is because all
common rafters are shortened half the thickness of the ridge
or 3/4". This allows the top of the common rafters to line
up with the top of the ridge at each end.

When framing a hip roof, always start with the common
rafters. This will place the ridge in its proper location.
This part of the roof is framed like a gable roof, but the
similarity ends there.

Start by nailing common rafters on one side of the ridge at
each end. Now raise the ridge and nail two rafters on the
other side of the ridge opposite the first two rafters. Once
this is done, push the ridge up so the birdsmouth cuts pull
in tight to the walls on each side of the building. These
rafters can now be nailed to the wall in their corresponding
locations in relation to the ridge. Now nail the two common
rafters to the center of the end walls and to the ends of
the ridge board. This will lock the ridge in its exact
location. The rest of the common rafters can be nailed to
the wall and ridge board.

The next parts to be installed are the four hip rafters.
These are nailed on the outside corners of the buildings
walls and in the intersection made by the end and first
common rafter where they meet at the ridge. With the hips
and common rafters in place, its easy to see why this makes
for such a strong and solid roof.

With the hip rafters in place the jack rafters can be
installed. Before nailing on the first jack rafter, a
string must be run from the plumb cut on the hip rafter to
just above the birdsmouth. This is a vital step in hip roof construction. This can be done by driving a nail in the center of the hip at the above mentioned locations. Tie the string to one nail, pull it tight, and secure it to the other nail. This is to ensure the hip rafter stays straight during the jack rafter installation. As the jacks are nailed on, the string should be kept at the center of the hip. To help keep the hip rafter straight, the jack rafters should be nailed on in pairs, first one side of the hip, then its mate on the other. This process is
continued all the way down the the hip rafter till all jack
rafters are installed on both sides of the hip. Remove the
string and repeat this procedure on the remaining three hip
rafters to complete the framing of the roof.

Collar ties and fascia boards will need to be installed
before the roof can be sheathed, but these are the basic
steps to framing a hip roof.