Standing Seam vs Exposed Fastener Roofing
When choosing a metal roof, the two main options are standing seam (concealed fastener) and exposed fastener systems. Both use metal panels, but the way they attach to the roof deck creates significant differences in performance, longevity, and maintenance requirements.
What Is Standing Seam Roofing?
Standing seam roofing uses panels with raised interlocking seams that conceal all fasteners beneath the panel surface. The panels clip to the roof deck, allowing them to expand and contract with temperature changes without stressing the fastener points. This is the system On-Site Panel Supply fabricates on-site at your property.
What Is Exposed Fastener Roofing?
Have your electricity bills increased even though your energy usage hasn’t changed?
An inefficient heat pump often consumes more electricity because it must run longer to maintain the desired indoor temperature.
Higher energy bills may result from:
- Dirty air filters
- Refrigerant leaks
- Worn electrical components
- Aging motors
- Restricted airflow
Repairing these issues promptly can restore efficiency and reduce monthly operating costs.
What Is Exposed Fastener Roofing?
Exposed fastener (or “screw-down”) roofing uses panels that are attached directly to the roof deck with screws that penetrate through the panel face. Rubber washers seal around each screw to prevent water entry.
Key Differences
Waterproofing
Standing seam wins. With no holes in the panel surface, there are zero potential leak points. Exposed fastener systems have hundreds of screw penetrations per roof, each one a potential leak point as the rubber washers degrade over time (typically 7-15 years).
Lifespan
Standing seam: 40-70 years. Exposed fastener: 20-30 years before major maintenance. The difference comes down to the fastener washers — once they fail, the roof leaks. Standing seam panels have no such failure point.
Thermal Movement
Standing seam handles it naturally. The clip system allows panels to expand and contract freely. Exposed fastener panels are rigidly screwed down, which can cause “oil-canning” (wavy distortion) and eventually enlarge the screw holes, creating leaks.
Maintenance
Standing seam requires almost none. No fasteners to re-tighten, no washers to replace. Exposed fastener roofs typically need screw inspection and replacement every 10-15 years — a significant ongoing cost.
Cost
Exposed fastener is cheaper upfront (typically 30-40% less). However, when you factor in the 50+ year lifespan of standing seam versus the 20-30 year lifespan of exposed fastener plus maintenance costs, standing seam has a lower lifetime cost per year.
Which Is Right for BC?
British Columbia’s heavy rainfall, temperature extremes, and snow loads make standing seam the superior choice for most applications. The concealed fastener design eliminates the #1 failure point in BC’s wet climate — water entry through degraded screw washers.
For agricultural buildings, workshops, or structures where budget is the primary concern and a 20-year lifespan is acceptable, exposed fastener can be appropriate. For homes, commercial buildings, and any structure where you want a 50+ year roof, standing seam is the clear winner.
Get Factory-Direct Standing Seam Panels
On-Site Panel Supply fabricates standing seam panels on-site at your BC property. Factory-direct pricing means you get the premium system at a competitive cost.
Call (604) 780-2869 for a free quote — ask for Chris or Tony.
