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.

A hip roof is a little more complex to frame 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

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.

Mike Merisko (C)2007