In simplest terms, pitch is the slope, or angle, of a roof. For every 12 inches toward the peak of the roof, the roof will rise a certain number of inches. For example, if there is a rise of 5 inches, the pitch is written 5/12. Depending upon the design and the materials used in its construction, a roof may have a steep pitch or a gradual one, but every roof has some kind of pitch.
Roofs made from shingles generally have steeper pitches. Determining the minimum roof pitch for shingles requires an understanding of how shingles work compared to other types of roofing materials. Determining roof pitch also requires an aesthetic eye; as in, what looks best? You’ll also need to take note of the strengths and weaknesses of shingle roofs so that you can determine what pitch your roof should ultimately have.
Shingles: What You Need to Know
When you think of the classic image of a roof, you probably imagine a gabled roof with a slope on either side, covered with shingles. There’s a reason this type of roof is among the most iconic images in our culture. Shingled roofs are inexpensive, versatile, and have been in use for many, many years.
Shingles can be made out of any number of materials, although nowadays, the most common material in North America is asphalt. Asphalt shingles are strong. With a base made from fiberglass, they’re rendered watertight by asphalt and strengthened by a layer of minerals. They last for decades and allow water to bead on top of them and roll off harmlessly. When they’re damaged by wind or other heavy weather conditions, they can be replaced fairly easily.
Shingles can also be constructed by a wide variety of other materials, including slate, metal, plastic, or wood. The material used varies depending upon the aesthetic needs of the home builder and can have a dramatic effect on the cost of the roof itself.
How Pitch Affects Your Roof
Just like the material your roof is constructed from has an effect on both its curb appeal and durability, so too does its pitch. A roof with a very steep pitch is particularly good at allowing water to roll off it. If you live in an area that’s especially rainy or snowy, a roof with a steeper pitch is probably a better option. Homes built in areas with less precipitation can usually get away with a narrower pitch.
While roofs with a high pitch are less vulnerable to the effects of rain and snow, they tend to be more vulnerable to damage caused by heavy winds. Wind shear is more likely to catch shingles on a steeper roof. If it does so, it can carry them away and necessitate replacement.
Deflection is also a concern with roofs; that is, the roof sagging due to a heavy load sitting on top of it. The narrower the roof pitch, the more material will accumulate on top of it. Snow can cause roof deflection if it can’t slide off the roof effectively, as can leaves, sticks, and standing water.
Your roof pitch affects your cost of heating and cooling as well. A lower-pitched roof means less square footage, which means a reduced energy bill. A higher-pitched roof may cost more for heating and cooling.
The final factor you must take into consideration regarding the pitch of your roof is the ease of repair. A roof with a steeper pitch is, of course, more difficult to repair because it’s more challenging to climb onto.
Determining the Best Roof Pitch for Your Home
If you’re constructing a new home and you wish for a roof with shingles, you’ll need to decide which of the above factors are most important to you. You’ll need to consider material costs as well: a steeper roof with more surface area will necessarily cost more. Repairs may also prove to be more costly; however, you may also avoid having to repair your roof as often due to the decreased chances for deflection and water damage.
In most cases, homeowners will discover that the optimal roof pitch is somewhere in the middle of the two extremes. While the absolute minimum roof pitch for shingles is 2/12, you’ll never actually want a roof this narrow because the deflection can be quite damaging. Similarly, a roof with a pitch that’s too steep can become hugely impractical to maintain and repair.
If you’re unsure of the pitch of your current roof, you can calculate it relatively easily. You simply have to find a rafter inside your home—the attic is usually the best place to do this—and place a carpentry level up against it. Mark twelve inches, and then measure upward from there. These numbers can then be entered into a roof pitch calculator like the one here.
Since maintenance is such a crucial part of any roof, it’s a good idea to have a professional roofer whose services you can utilize when necessary. Especially if you have a steeper roof, where it’s difficult for you to perform repair jobs on your own, you’ll need a good roofer who’s committed to performing the job safely and effectively. Finding one in your area will take a bit of research. You need to thoroughly vet your roofer’s experience and check references. The best companies have been in business for multiple decades. For example, Interstate Roofing has been maintaining and repairing roofs for over 30 years. In that time, we have installed and repaired roofs made from every material and of every pitch.