Roofs today have changed dramatically from many years ago. We now have a variety of materials to choose from, sustainability and environmental factors to consider, and with ever increasing hailstorms, the all-important impact resistance rating. But what about the roofing slope?
A roof’s slope, or pitch, is its vertical rise divided by its horizontal distance (or run). Slope is typically expressed with the rise first and run second, with the run denominated by the number 12, giving a ratio of how many inches of incline there are to each 12 inches (one foot) of run. For example, 3:12, 4:12, 5:12, and so on.A pitch between 4/12 and 9/12, is the most common in residential work, and roofs with a pitch exceeding 9/12 (37 degrees) are termed steep slope roofs. A low-slope roofs is a roof with a pitch between 2/12 and 4/12. Roofs with a pitch of less than 2/12 are considered flat, even though they technically have some slope.
So why does slope matter? Here are three reasons:
Walkability. While no roof is truly flat, but rather slightly pitched to allow for water drainage, the steeper the slope, the more difficult to not just to walk on your roof, but to perform regular maintenance, inspections, and small repairs.
Materials. Some materials are better suited to high-pitch roofs than low-pitch roofs. Why? As water drains less quickly from low-pitch roofs, materials need to be more resistant to water and leaks. On the other hand, high-pitch roofs require more materials (due to greater surface area), and therefore weight becomes a consideration.
Impact resistance. While most homeowners use aesthetic appeal as a determining factor for roof pitch, the pitch of a roof matters a lot when considering impact resistance and hail damage. Particularly in climates that experience both hail and snow, high-pitch roofs minimize ice damming. But, because there is less horizontal surface area exposed, they fair better against hail. And because they drain better than low-pitch roofs, high-pitch roofs are less likely to have water leaks.
Whether you are in the process of designing your future home or re-roofing you current one, it is best to first meet with a licensed roofing professional who can help you choose the options that are best for you and your home.
This article was brought to you by ASAP Roofing, a national leader in roofing restoration, weatherization, and hail damage. ASAP has offices in Aurora, Colorado, Dallas, Texas, and Indianapolis, Indiana.