There are a number of different roof styles and materials for you to choose from.
The style of roof on a house does much to help characterize the home. Take a mobile home for example. The flat, metal roof quickly identifies the home as a mobile.
Roof pitches are determined by the measurements of their rise (the measurement from the top of the wall to the peak of the roof) and their run (the distance from the outside wall to the center of the house). You will hear your roof pitch described something like this "a four and 12 elevation," which means the roof rises four inches for every 12 inches it runs.
There are a number of different roof styles, as the following show:
Gable roof. One of the most commonly used styles, a gable roof consists of two sides of equal size that peak in the middle. It is simple to build, and can be steep or more on the flat side.
Hip roof. Unlike the gable roof that has two sides that peak in the middle, the hip roof has four sides that slope downward. It also involves a bit more work to build.
Mansard roof. A unique style that, put simply, resembles an upside-down casserole dish. The top is shaped similar to a rectangle fanning out at the bottom into an overhang.
Pyramid hip roof. Similar to the hip roof, but the sides meet in a point at the peak.
Gambrel roof. Better known as a barn roof.
Saltbox roof. Like a gable roof, but one side is much longer than the other, allowing for extra living area on one side of the house...
Read the full article in the CalFinder Remodeling and Home Solar Power Magazine