Many homeowners do not consider roof slope or design as contributing factors to hurricane damage. People often assume age, material type, and quality of installation are the most important factors.
Roof slope and roof design, though, are incredibly important factors during hurricanes and tropical storms. It’s similar to the aerodynamic design of a race car vs. a box truck. One will cut through the wind, and the other has a high drag coefficient.
Lloyd Roofing has built, repaired and replaced thousands of Florida roofs, many of which have endured hurricanes and tropical storms. Property owners rarely consider roof slope and design in their list of “must haves” when purchasing a home or business. However, those elements impact a roof’s expected lifespan in a sub-tropical climate like Florida. Additionally, many insurance companies offer premium discounts for certain types of roofs.
Types of Roof Styles
There are more than a dozen architectural styles for roofs. In Florida, two common types of residential roof styles are prevalent across the state:
- Gable roof: A gable roof has two sides that meet at an elevated center ridge and slope down to the side. The gable is the triangular end below the roofline.
- Hip roof: A hip roof has four sides that touch the elevated center ridge and slope down to the side. Commercial buildings also feature gable and hip roofs, in addition to a third type:
- Flat roof: A flat roof is essentially parallel to the ground, making it ideal for buildings with a larger square footage.
The Impact of Roof Slope
Roofs, just like homes, come in all shapes and sizes. Even within a planned development, individual units or buildings will feature different roof styles.
Slope is defined as the degree of roof incline measured by the ratio of the rise in inches to the run in inches. An 8% slope, for example, means a roof would rise one foot vertical for every 12 feet horizontal.
The Florida Building Code spells out minimum slopes for various roofing materials:
- Asphalt shingles: 17% slope or greater
- Metal: 2% slope or greater for standing seam, 4% slope or greater for lapped seam with applied lap sealant and 25% slope or greater for lapped seam without applied lap sealant.
- Clay and concrete tile: Varies by type, size, weight and other factors
- Flat: 2% or greater
Even a flat roof is not truly flat. That is by design. A slope allows positive drainage to redirect rainwater to the ground and avoid pooling on a roof structure.
Top-performing Roof Styles
No roof installation is the same and none are easy. Installation time is a factor in pricing, so a higher-sloped roof on a 2,500-square-foot home with multiple architectural design features often costs more than a lower-sloped roof on a similar structure. It’s all about installation time.
Performance-wise, though, hip roofs earn praise for their ability to redirect high winds that come from all four directions. A gable roof, on the other hand, only has that capability if the wind comes from two directions. The U.S. Department of Energy’s Building America Solution Center notes hip roofs perform better in high winds, offer better drainage and potentially can lower home insurance rates.
Although it’s commonly believed that lower-sloped roofs perform better during hurricanes, research hasn’t always agreed. An Oak Ridge National Laboratory study of roof damage following Hurricane Katrina found that buildings with steep sloped roofs held up better against the wind. That surprising result was attributed to the building materials composing the steep sloped roof structure offering better protection against wind uplift forces. Homes with steep roofs were built with extra reinforcements.
Taking the Next Step
Since 1851, a total of 122 hurricanes have made landfall in Florida. Weather forecasters continue to predict active hurricane seasons, and builders continue to refine architectural plans to create more resilient structures.
Lloyd Roofing specializes in post-storm repairs and replacements, as well as roof design. Are you ready to design, build or replace a roof? CONTACT US to get started.