5 Ways Fastener Troubles Can Cause Leaks On A Metal Roof


Metal roofs aren't typically prone to leaks, but they aren't immune to them either. Often leaks occur at the weakest part of the roof, which on a metal roof is where the fasteners are driven into the panels. 

1. Screw Misalignment 

A properly inserted screw should be installed perpendicular to the roof panel slope. If the screw enters at an angle, there will be a gap on one side between the screw head and the roofing panel. Water can seep into this gap and pool beneath the panel. Eventually, the water will then leak into your home below. Replacement of misaligned screws and their washers fixes the issue.

2. Location Error

Where roofing screws are installed is just as important as how they are installed. The screw should penetrate the roofing panel and enter the wood or metal roof framing below. Failure to do so means your roofing panel isn't properly anchored and there is a hole to nowhere under the screw that can lead to a water leak. It's necessary to remove the screw and seal the hole before installing a new screw at a better location.

3. Under-Driven

An under-driven screw is one that isn't screwed in completely so there is a space between the screw head and the metal roofing panel. Water can run under the screw and into the hole. Tightening the screws properly and making sure a washer is in place between the screw and the roof is needed to prevent the leak from becoming worse. 

4. Over-Driven

Over-driven screws are the opposite of under-driven, and they are just as likely to cause a roof leak. If a screw is put in too tightly, it will cause the metal roof panel to bow around the insertion point. This compromises the flush fit necessary between the screw and the metal panel. Any gaps that form around the overly tight screw can let water seep under the metal panel. 

5. Washer Failure

Roofing screws on a metal roof have a rubber washer between the screw head and the metal panel. The washer acts as a gasket to create a watertight seal around the entry point of the screw. Over time these washers can begin to crack or fall apart due to weathering and age. Your roofer can replace the washers and fasteners to recreate the seal. They may also seal over each screw for an added layer of leak defense.

Contact a roofing contractor in your area for more help. 


11 January 2023

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