Exposed fastener versus standing seam roofing
As the name implies, exposed fastener systems will feature fasteners exposed to the external environment after installation. The heads will be clearly visible to viewers of the completed building. However, these are often painted to match the color of the roofing panels. SFS has a color-matching tool that helps customers ensure their exposed fasteners blend in perfectly with whichever panel they use.
In contrast, standing seam roof systems have no exposed fasteners after installation. Instead, metal clips are utilized to attach the roofing panels to the deck. No products are installed into the physical panels, and this results in a less intrusive appearance.
Pros and cons of exposed fastener systems
Advantages | Disadvantages |
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Pros and cons of standing seam systems
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Cost and labor: standing seam versus exposed fastener
Exposed fastener systems will almost always be a less expensive option when compared to standing seam systems. This is due to both the reduced material costs and simplified labor requirements.
Exposed systems only require metal panel and fastener components for installation into the roof-deck. However, standing seam systems require metal panels, panel specific clips, and appropriate clip screws. This results in additional material costs and complexity.
Standing seam systems are installed by clamping metal panels to the roof deck with specialized clips. Installers will need to lay out the panels, attach clips to the panels, install the clips into the deck, and, for some systems, seam the metal panels together. In contrast, exposed systems only require the installation of the metal panels directly to the deck. This results in a large reduction in labor complexity for exposed systems. Installers will require less training, and installation will typically require less time for these systems.
Appearance: standing seam versus exposed fastener
One of the major downsides to exposed fastener systems is the appearance of fastener heads on the roofing panel. There have been many improvements in both color matching technology and low profile head design to ensure the least obtrusive appearance for these systems. However, most observers agree that standing seam systems, which feature no external fasteners, provide a smoother and more appealing profile.
Corrosion performance: standing seam versus exposed fastener
Due to the lack of external parts on standing seam systems, there is a lower probability of corrosive damage occurring. However, exposed fasteners are susceptible to external environmental conditions. If these fasteners have a lower corrosion rating than the metal panels used, rust will begin to appear earlier. Additionally, due to potential differences in fastener material and panel material, some systems may be damaged by galvanic corrosion, which occurs when two separate metals are in contact and moisture is applied. In contrast, standing seam systems will not be susceptible to these types of issues.
Applications: standing seam versus exposed fastener
Certain applications are better suited for each respective roofing system.
Exposed systems have a number of limitations that will restrict usage on some jobs. For instance, due to thermal movement, exposed systems typically should not be used for long panel runs. This is because changes in roof temperature will cause slotting in the panels. This type of damage increases the size of holes created during fastener installation and may lead to leaks and structural damage. In addition, damage may occur when used on low slope roof pitches (smaller than 3:12).
In contrast, some standing seam systems are rated lower than exposed systems for wind uplift. This is a value utilized to determine the wind pressure that a roof can sustain before permanent deformation occurs. A designer should ensure the uplift rating of the system used is acceptable for the required application.
Maintenance: standing seam versus exposed fastener
Standing seam systems typically require less maintenance than exposed fastener systems but are much more difficult to repair.
Maintenance on exposed systems typically consists of replacing damaged fasteners. The damaged fastener is removed and replaced with a larger diameter fastener. As a result, the metal panels are usually still acceptable after failure of exposed fasteners. In contrast, failures on standing seam systems are exceptionally difficult to repair and may require extensive replacement of panels, clips, and fasteners. This requires additional labor and materials.