The most common porch roof is a gable roof. The gable roof is a triangular shaped roof that projects along a ridge down the center of the enclosure. The sides are sloped at a particular pitch rise over run to shed snow and water. For instance a 6/12 roof pitch means the roof elevates 6’ over a 12’ span. Gable roofs usually overhang the walls of the enclosure on the sides thus creating the need for soffits and fascia. Gable roofs are familiar forms and blend in well with many house designs. The peak of a porch gable roof can sometimes create problems if it interferes with house windows.
A hip roof is a more complicated roof style where all the roof sides slope downwards to the walls. There are no gables and the slope is generally relatively gentle. A square hip roof is shaped like a pyramid. Hip roofs are more difficult to build than gable style roofs because they require a more complicated set of roof trusses. They have the aesthetic advantage of providing a solid, compact appearance for the structure.
A shed style porch roof involves a single sloping roof surface that attaches to the house wall on the high end and to support posts on the low end. The shed style roof is common for long and narrow front porches. It doesn’t usually make sense to include a shed style roof over a deep porch because the roof line at the house will be too high and it will look out of place.