Metal Roofing

Metal roofing comes in three main residential forms, each with different performance profiles and cost points.

Standing seam is the premium option. Panels run continuously from ridge to eave with raised interlocking seams that keep fasteners completely concealed. Because there are no exposed fasteners, there are no fastener holes to leak or fastener heads to weather. Standing seam is the system architects and high-end builders specify. It's also the most installer-dependent: proper clip installation, panel alignment, and seam engagement require training that most asphalt roofers don't have.

Metal shingles (also called metal shake or stone-coated steel) are pre-formed panels that replicate the appearance of asphalt shingles, wood shake, or tile. They're installed with exposed fasteners, which is a maintenance consideration, but they're significantly less expensive than standing seam and installable by more contractors. Stone-coated steel products carry the added benefit of quiet installation — the stone coating absorbs rain sound.

Exposed-fastener corrugated panels (R-panel, 5V crimp) are the traditional barn and agricultural profile. Perfectly functional and durable but aesthetically industrial. Used on some residential projects where budget is the primary driver or the profile fits the architectural style.

The two dominant metal roofing materials are Galvalume steel (a steel substrate with a zinc/aluminum coating) and aluminum.

Galvalume steel is the most common material for standing seam and panel systems. It's harder than aluminum, more resistant to denting from hail, and less expensive. The zinc/aluminum coating provides excellent corrosion resistance in most climates. One limitation: within a few hundred feet of saltwater or in high-chloride environments, galvanic corrosion can be a concern. In Northeast Mississippi (far from the coast), Galvalume steel is typically the right choice.

Aluminum is corrosion-proof in any environment and the right choice for coastal or high-humidity applications. It's softer than steel — which means it's more susceptible to denting from large hail — but it weighs less (30% lighter than steel) and carries no risk of the red rust that can occur at cut edges on steel panels.

Copper and zinc are architectural metals used in specific high-end applications. Both develop attractive patinas over time. Both are priced at a significant premium over steel or aluminum ($20-40/sq ft installed for copper).

The argument for metal roofing is fundamentally economic, even though the upfront cost is higher.

A standing seam metal roof installed today at $14/sq ft on a 25-square roof costs approximately $35,000. An architectural asphalt roof at $5.50/sq ft costs $13,750. The difference is $21,250.

Over 50 years, the asphalt roof will be replaced once (potentially twice, depending on lifespan). Each replacement adds $13,750-18,000 plus the disruption and the recurring cost of maintenance, repairs, and insurance claims. The metal roof, properly maintained, runs the same 50-year window with no replacement and minimal repair cost.

Total lifetime cost analysis typically shows metal roofing breaking even with asphalt at the 20-25 year mark, and saving $10,000-30,000 over 50 years depending on material and labor costs at replacement time. The break-even assumes the homeowner stays in the home — which is why metal's economics favor long-term owners specifically.

Metal roofing's reputation for storm resistance is earned. Standing seam systems with concealed clips are tested to 140-160 mph wind uplift resistance — well above the wind speeds associated with most tornadoes below EF2, and significantly above the 130 mph threshold of Class G asphalt shingles.

The key to that performance is the clip system. Hidden clips allow the panel to float — expand and contract with temperature changes — while maintaining contact with the structural deck. A standing seam roof installed with fixed clips (a shortcut some contractors take) loses the expansion tolerance and is more prone to oil-canning (visible waviness) and fastener stress over time.

For hail: steel is harder than asphalt and more resistant to surface denting from standard hail (1 inch or smaller). In a severe hail event (2 inch+), both materials can sustain visible impact marks, but metal damage is typically cosmetic rather than structural. Aluminum dents more readily than Galvalume steel under hail.

Metal roofing installation is a specialty. The material tolerates less margin for error than asphalt, and errors that would be cosmetic on an asphalt roof can become functional problems on metal.

Critical execution points:

Thermal movement: Galvalume steel panels expand and contract approximately 3/8 inch per 10 feet of length across the typical Mississippi temperature swing (0°F to 110°F surface temp). The clip system must allow for this. Panels fastened too rigidly will buckle or pucker.

Dissimilar metals: Where metal panels contact copper pipe boots, copper flashing, or copper gutters, galvanic corrosion will occur. Installation requires non-conductive separators or specified compatible flashing metals.

Fastener specification: Exposed-fastener systems require neoprene-washered screws torqued to the correct specification. Over-torqued screws compress and eventually crack the washer; under-torqued screws pull through in wind. Both fail the same way — from the outside, with water behind them.

Underlayment: Metal panels run hotter on the surface than asphalt (they also cool faster at night). Standard felt underlayment degrades more quickly under metal than under asphalt. Specify a high-temperature synthetic underlayment or a vented underlayment system.

Metal roofing's reflective properties are a genuine benefit in Mississippi's climate. A bare Galvalume steel panel reflects 60-70% of solar radiation; a painted panel with a "cool roof" pigment can reach 70-85% reflectance. By comparison, a standard dark asphalt shingle reflects 5-20%.

In practical terms: a well-designed metal roof can reduce attic temperatures by 20-35°F compared to asphalt in peak summer conditions. That reduction translates to lower cooling load, reduced HVAC run time, and potentially meaningful energy savings on a poorly insulated home.

The caveat: the energy savings depend heavily on whether the attic is properly insulated. If attic insulation meets current code (R-38 or better), the temperature differential between a metal and asphalt roof has diminishing effect on conditioned space below. Metal's energy benefit is most pronounced on homes with under-insulated attics or on homes where the living space is directly below the roof deck (cathedral ceilings, finished attic spaces).