April 16, 2021

AG Panel Fastening Process

Correctly fastening the DuraFast™ AG panel is a critical step that secures the integrity of the roofing system. More than anything, the team at Wagner Metal Supply wants customers to be satisfied with their metal roofing purchase. Part of customer satisfaction includes thoroughcustomer education regarding proper installation. If the product is installed incorrectly—this can cause you to be unhappy with the product. The fastening process can make or break a roofing system. Continue reading to learn more about precautions, improper, and proper AG panel fastening methods.

Precautions for Fastening DuraFast™ AG Panels

Before any roofing panels are laid, ensure the screws you are using are fit for the job. The standard size metal roofing screw is 1 ½”. Keep in mind that not all screws are created equally. Ensure the screws you use for your metal roofing application are galvanized. Galvanized metal roofing screws will not rust or crumble as ordinary screws would when facing the elements overtime. Next, be cautious about how the screw is driven into the substrate. A weathertight seal on the roofing system can be compromised when the screws are driven incorrectly. A properly driven screw should have the rubber washer snug against the roofing panel for a suitable seal. Here are two ways to recognize if your screw is underdriven or overdriven.

  • Underdriven

    Underdriven One way to tell if a screw is underdriven is by looking at the washer. If the washer is not snug and in contact with the roofing panel—the screw is underdriven.

  • Overdriven

    Overdriving a screw will create a poor seal between the washer and the metal roofing panel. If the panel seems to be dented from the screw and the washer appears overly compressed—the screw is overdriven.

Improper Placement for Fastening DuraFast™ AG panel

  1. It causes damaging pressure to the panel

    This pressure on the panel will cause it to bow. If this happens, deformation around the fasteners at ground level will be incredibly noticeable. It is also extremely easy to unintentionally overdrive the screw on this location of the panel.

  2. It does not allow for a proper seal

    The rubber washer that seals the screw penetration into the metal panel is not as wide as the rib of the panel. This could lead to premature deterioration of the roofing system.

  3. The screw cannot be drilled into the substrate at its full length when drilled on the rib.

    A screw utilized for metal roofing is 1 ½” in length. Most ribs of metal roofing AG panels stand ¾ of an inch away from the substrate. Drilling from this location will leave ¾” of the 1 ½” screw fastened into nothing leaving an empty space.

Proper Placement for Fastening DuraFast™ AG Panels

Proper placement for fastening AG panels should be along the flat of the panel. One factor to keep in mind is that it is natural for a metal roofing system to slightly compress and expand in varying weather conditions. When a fastener is located at the rib of the panel—it will loosen the fastener as it moves. This will eventually cause the fastener to fall out of the substrate. When placed on the flat—it allows the panel to naturally expand and compress without moving the screw. Proper fastener placement means everything to the roofing system. Correctly fastening DuraFast™ AG panels extends the life of the roof to 40 years or longer!


An AG metal roofing panel has a series of ribs and flats in its design. The fasteners should be driven through the flat of the AG panel for optimal performance.
Fasteners are recommended to be placed along the flat of the AG panel and not the rib for 3 reasons. Driving a fastener into the rib will create unnecessary pressure on the panel, it won’t allow for a proper seal, and the screw will not be driven into the substrate to its full length.
Examine how you’re driving the screw to ensure your AG panel is properly secured to the substrate. You want to make sure the screw isn’t overdriven or underdriven. Both overdriving and underdriving the screw will compensate for the weathertight seal of the roofing system. Ensure that the rubber washer is snug against the roofing panel without being overly compressed. You can also ensure your metal panel is properly secured by driving the fastener into the flat of the panel—not the rib.
Improper screw penetration will put the roofing system in jeopardy. AG panel metal roofing systems are prized for their durability, weathertight qualities, energy-efficiency, and longevity. Failing to properly fasten these panels to the substrate puts all these incredible qualities at risk for deteriorating prematurely.