Standing Seam vs. Corrugated Metal Roofing

What is the difference between standing seam and corrugated metal?

Standing seam panels join at raised seams with hidden clips or nail strips, while corrugated panels overlap side to side and are fastened with screws driven through the panel face. That one difference drives most of the other contrasts in cost, maintenance and appearance. Corrugated metal has a rolling wave profile; similar exposed-fastener panels have trapezoidal ribs and are often sold as ag panel or ribbed panel. All of them rely on rubber or neoprene washers under each screw head to seal the hole. Standing seam has flat pans and tall seams with no fasteners in the field of the roof. Water runs down the pans and never crosses a screw hole, which removes hundreds of potential leak points. The tradeoff is more precise fabrication and installation, which costs more.

Why is corrugated metal roofing less expensive?

Corrugated and other exposed-fastener panels are less expensive because the panels are simpler to make and faster to install. Crews fasten the sheets directly to purlins or the deck with screws, overlap the edges and move on, without clips, seaming or the detailed flashing that standing seam requires. The panels are often thinner, come with fewer trim options, and can go over open framing on barns and sheds where no solid deck is used. That lower upfront cost is real, but it is not the whole picture. Exposed fasteners need attention over the years, and leaks at screw holes can damage the structure below. For a house, maintenance and the risk of water damage belong in the comparison. Prices on our cost page are a rough guide only — every roof is priced individually, and structural or other site conditions can move the number. An in-home roof consultation is the only way to get accurate pricing for your home.

Which roof stays watertight longer?

Standing seam generally stays watertight longer with less maintenance, because its fasteners are hidden and protected from the weather. On an exposed-fastener roof, the washers under each screw face sun, heat and cold and can harden, crack or loosen over the years, and screws can back out as panels expand and contract. New England's climate makes this more noticeable. Freeze-thaw cycles, heavy snow sitting on the roof, ice at the eaves and summer heat all work on screws and washers. Owners of corrugated roofs typically need to inspect fasteners and replace washers or screws periodically. Standing seam has its own weak points, mainly at flashing, penetrations and eaves, but there are far fewer of them. With either system, a solid underlayment and good flashing are what protect the house when water does get past the outer layer.

How do they compare in snow and coastal conditions?

Both shed snow, but standing seam's smooth pans usually release it more cleanly, while corrugated ribs and exposed screw heads can hold snow and ice a little longer. Either way, sliding snow over doors, decks and walkways needs to be planned, and snow guards are a design decision for those areas. On the coast, the material matters more than the profile. Painted steel panels rely on their coating to resist rust, and with exposed fasteners there are hundreds of drilled holes and screw heads where salt air can start corrosion. Aluminum panels do not rust in either style, which is why aluminum is a strong choice on Cape Cod, the Islands and the Maine coast. Ice dams are unrelated to profile. They come from heat loss and ventilation in the house below, and no roof prevents them by itself.

When is corrugated metal the right choice?

Corrugated or other exposed-fastener metal is often the right choice for barns, sheds, garages, sugarhouses, carports and other outbuildings where cost matters most and occasional fastener maintenance is acceptable. It has a long history on New England farms and suits that agricultural look. Some homeowners also like corrugated for a rustic or industrial style on porches or accent roofs. If you use it on a heated house, plan for a solid deck, good underlayment, proper ventilation and a maintenance schedule for the fasteners. For the main roof of a home, most homeowners choose concealed-fastener systems such as standing seam or interlocking metal shingles, because the fasteners are protected and the roof needs less upkeep. Interlock's profiles are Slate, Cedar Shingle, Shake, Mediterranean Tile and Standing Seam, plus solid copper.

How do the two look on a New England house?

Standing seam looks clean and refined, with evenly spaced vertical ribs and flat pans, while corrugated has a busier, wavy texture with visible rows of screws. On a modern farmhouse or contemporary home, standing seam usually reads as the more finished choice. Corrugated looks at home on a barn or shed and can look out of place on a Colonial, Cape or Victorian. On historic houses, neither may be the best match; a profile that looks like slate or cedar often suits traditional New England architecture better. If you live in a historic district, check with your local historic district commission before choosing any metal profile, because some commissions have specific views on exposed fasteners, seam spacing and color.

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