Given the types of roofing material types available today, one would think that choosing the roofing material is a matter of aesthetic choice. But there is one factor that informs the choice of roofing material: roof pitch. In this blog, Howard Roofing & Home Improvements takes a closer look at how roof pitch relates to choosing the roofing material.
Roof Pitch Basics
Roof pitch is represented either as a fraction or as a ratio. For example, let’s take one of the most common residential roof pitches, 4/12, or 4:12. The number 4 represents four inches of “rise,” the vertical measurement of a roof pitch. The 12 represents 12 inches—that is, 1 foot—or the horizontal measure. Therefore, in this example, 4/12 pitch means 4 inches of rise for every foot of run.
To calculate your existing roof’s pitch, find a horizontal beam perpendicular to the roof edge. Mark a 12-inch section on it, then measure the height from the first point to the rafter directly above it. Do the same with the other point, then subtract the difference between the two figures, which becomes the rise for every 12 inches of the roof. You may need to do it more than once on roofs with multiple pitches, such as on Mansard roofs.
How Roof Pitch Affects Roof Material Choice
You might be surprised to learn that even flat roofs have a slight pitch. Roofers build them that way to prevent ponding water. A “flat” roof is pitched between 0.5/12 to 2/12. Beyond that, a roof may be considered a low or gently-pitched roof. While steep-pitched roofs are more efficient at shedding rainwater, it’s not a practical solution the bigger the building is. Just imagine what a thousand-square-foot property would look like with a steep-pitched roof. It would be extremely difficult to maintain, would require exceptionally large gutters, and would look comically large.
What many people don’t know is that the roof pitch dictates the kind of roofing material that can be installed on it. Asphalt shingles, slate, and tile are designed for pitched roofs because it relies on gravity to route rainwater to the roof edge. Steep roofs are also visible from the ground and can help boost curb appeal. The same roofing materials wouldn’t work on a flat roof, which is why it’s often fitted with single-ply or built-up roofing.
Howard Roofing & Home Improvements is the roofing contractor to turn to for all your roofing needs. Give us a call at (636) 333-1690 or fill out our contact form. We serve customers in St. Charles, MO, and surrounding areas.