Whether you are framing a gable or hip roof on your home, there are considerations to make for both types. If you are unsure which way to go, however, compare them in terms of cost, level of difficulty, strength, and look. There are pros and cons for each, and it may be that the structure of your home is better suited to one or the other. If this is not the case and you have a choice to make, weigh practical and aesthetic concerns equally before deciding.
Look first at the construction of the two roof types. Gable roofs have two faces, whereas hip roofs have four, meaning that the construction of a hip roof is more involved. Gable roofs are comprised of two sets of parallel rafters that attach to the truss, angle up and meet at the ridge board, the piece of lumber extending the entire length of the structure. When in place, the vertical sides of the structure reach up to the fascia, making a triangular shaped top.
A hip roof, on the other hand, consists of a shorter ridge board along with several types of rafters: common, jack, end, and hip rafters. Consequently, it is more complicated. On a gable roof, rafters meet at the ridge board. On a hip roof, common rafters meet at the ridge board; end rafters must meet the ends, hip rafters slope up from the corners to meet the ridge board at 45 degrees, and jack rafters intersect the hip rafters all the way up to the ridge board from perpendicular sides. Both roof types require precise measurement, cuts, and installation, but hip roofs have more elements that can go wrong.
Provided there is one square foot of ventilating ability for every 150 square feet of attic or crawl space, there is no ventilation advantage that one roof has over the other. Gable roofs can use gable vents which install into the siding of the home. Ridge vents are also used with gable roofs. Box or dome vents work just for either roof type, as will under-eave or soffit vents.
Even if the roof square footage works out to be the same between a gable and a hip roof, a contractor will likely spend more time framing a hip roof. This means a gable roof is ultimately more affordable in terms of installation.
Gable roofs differ greatly in look from hip roofs. They allow for fully exposed sides, while hip roofs sit atop the boxed structure, revealing the same amount of siding on all sides. If the cost of installation is all the same to you, the look of the roof will be the final deciding point. Consider how you want your home to look and pick the roof type that most suits your vision.
If you live in a region affected by hurricanes, some argue that hip roofs are stronger than gable roofs in very high winds. Others say there is no evidence to support this. Thus, strength is usually not an issue. The pros and cons of each, then, revolve mostly around cost and level of difficulty to create.