Why Low-slope Roofs Aren’t Ideal For Exposed Fastener Metal Panels

By Evelyn Witterholt. 

Learn why roofs with lower slopes are not a great fit for exposed fastener metal panels. 

Although metal roofing is one of the most high-performing types of roof on the market, problems can still arise if certain installation factors are not considered. One major consideration to make when deciding on a type of metal roof panel is the slope of the roof itself. McElroy Metal discusses this subject more in-depth on their blog where they state that “exposed fastener panels aren't appropriate for slopes below 1:12.” 

The following are just a few things to consider when installing exposed fastener metal panels on lower slope roofs: 

Panel side laps 

Panel side laps are the area where two metal panels overlap. On low-slope roofs, this area is prone to water leakage through capillary action, where water enters the narrow space of the side lap. This issue can be fixed by applying a butyl seam sealant in the lap area, but this is recommended only for roofs with a slope of 3:12 and 1:12.  

Design of the panel 

In order to be installed, the exposed fastener panels must have a screw pierce through themto secure the material to the structure below. When rain or snow hits, a roof with a higher slope will allow the water to slide down the roof. But a roof with a lower slope won’t allow the water to slide down as easily, leaving a roof with more exposed areas at greater risks for leakage. 

If the fasteners on the panel are installed properly, water damage is less likely to occur. But if the fastener is too loose or too tight, when it’s submerged with water that’s not sliding off, the roof is more at risk of water damage. This is why McElroy Metal suggests using exposed fastener metal panels on roof slopes above 1:12. 

Read the entire article to learn the rest of the considerations to make about roof slope and exposed fastener metal panel selection. 

Learn more about McElroy Metal in their directory or visit www.mcelroymetal.com. 

About Evelyn  

Evelyn works as a writer for RoofersCoffeeShop, MetalCoffeeShop and AskARoofer. When she isn’t writing about roofing, she’s either at the gym lifting weights or curled up on the couch watching a movie.