Is Aluminum Siding or Wall Cladding a Good Fit for North Carolina Homes?

Aluminum wall cladding is exterior siding made from formed aluminum panels with a factory-applied finish. It covers the walls the way a metal roof covers the roof: as a durable, weather-shedding skin over a water-resistive barrier and the wall sheathing.

Interlock Roofing makes aluminum wall cladding as well as roofing. Homeowners use it in a few ways: as full siding for the whole house, as an accent on gables, dormers and upper stories, or to match a new aluminum roof so the exterior reads as one design. On many North Carolina homes, the gables and dormers are the hardest walls to reach for painting and the first to show weather, which makes them a natural place to start.

Aluminum is light, so it adds little load to the wall. It does not absorb water, it does not rot and it is not food for insects. Its factory finish means there is no regular repainting schedule like there is for wood. Those properties matter more in North Carolina than in drier, milder places, because heat, humidity and storms are hard on most siding materials.

Siding holds up in hurricanes only as well as it is fastened and detailed. FEMA's hurricane recovery guidance on siding in high-wind regions states that siding is frequently blown off the walls of residential and non-residential buildings during hurricanes, and that loss often starts at the lowest course and works its way up.

The same guidance points to a second problem: wind-driven rain is frequently blown into wall cavities even when the siding itself stays on. That is why the layer behind the siding matters so much. A properly lapped and taped water-resistive barrier, such as housewrap or building paper, sheds water that gets past the siding and limits airflow through the wall. Flashing at windows, doors and the base of the wall sends that water back out.

Whatever siding you choose, ask the installer how the starter strip and lowest courses are fastened, what fasteners are used and how windows and doors are flashed. Those details decide performance in a storm more than the siding brand does. See hurricane roof prep and hurricane-resistant roofing.

Aluminum suits coastal salt air because it does not rust. Steel siding and trim depend on zinc-based coatings that salt wears away, starting at cut edges, scratches and fastener holes. Aluminum forms a thin oxide film that protects it and re-forms when scratched, which is why aluminum is the standard material for boat hardware and coastal trim.

FEMA's coastal guidance says metal corrosion is most pronounced on homes within about 3,000 feet of the ocean, and its siding guidance recommends stainless steel fasteners for buildings in that zone. It also advises that aluminum trim be fastened with aluminum or stainless steel fasteners and that dissimilar metals not be used together. Those rules apply directly to aluminum cladding on the Outer Banks, Topsail, Wrightsville Beach, the Crystal Coast and the Brunswick County beaches.

Corrosion-resistant is not the same as maintenance-free. Rinse salt from sheltered walls under porches and deep eaves a few times a year with a garden hose, and keep copper gutters and flashings from draining onto aluminum. Our guides to salt air and metal roofs and aluminum vs steel on the NC coast cover the same principles for roofs.

Aluminum siding handles inland heat and humidity well because it does not take on water. In the Triangle, Charlotte and the Triad, the common siding problems are rotting wood trim and siding on shaded or splash-prone walls, peeling paint, and mildew on north-facing walls that stay damp. NOAA describes North Carolina's climate as humid with very warm summers, and that combination works against any material that absorbs water.

Aluminum does not swell, rot or split. A factory finish resists fading and chalking, and a smooth surface gives mildew and algae less to hold onto, though shaded walls can still collect pollen and organic film that a gentle rinse removes. Never pressure wash siding of any kind; it drives water behind the panels.

The wall assembly still needs to manage moisture. Humid air, rain that gets past the siding and condensation all need a path out. A properly installed water-resistive barrier, flashing at openings and good gutter drainage keep the wall sheathing dry. If you see mold or soft spots where old siding comes off, the cause needs fixing before new siding goes on. See roof algae and mold in humid NC for the moisture side.

Aluminum compares well on durability and upkeep, and each material has its place. In plain terms:

• Vinyl is common and economical. It does not rot, but it relies heavily on correct nailing to stay on in high wind, and FEMA's siding guidance spends much of its attention on vinyl installation details for that reason.
• Fiber cement is heavy and rigid, and it is common on many newer North Carolina homes. It needs painting over time and careful detailing at cut edges and joints to keep water out.
• Wood looks traditional and suits historic homes, but in a humid climate it needs regular painting and is prone to rot where it stays wet.
• Aluminum does not rust, rot or absorb water, carries a factory finish, and is light. It costs more than vinyl and can dent from a hard impact.

Prices vary widely with the house and the product, so compare written estimates for the specific wall areas rather than relying on general figures. Ask each installer the same questions about fastening, barrier and flashing so the bids are comparable.

Siding does not have to match a new metal roof, but coordinating the two often makes the house look finished. A common approach is a darker roof, such as Deep Charcoal or Black on an aluminum slate-profile roof, with lighter walls and aluminum cladding on the gables or dormers in a color that ties the two together. On farmhouse and coastal designs, cladding in a related tone can carry the roof color down to a porch or bump-out.

Doing the roof and the cladding together has practical benefits too. The crew can integrate the roof-to-wall flashing, the kick-out flashing at the bottom of each roof edge and the gable trim in one sequence, instead of cutting into new siding later to reach a flashing. Those roof-to-wall joints are among the most common leak points on any house.

Check HOA guidelines and historic district rules before choosing materials and colors. In a local historic district, North Carolina law requires a certificate of appropriateness before exterior changes, and it counts the kind and texture of building material as an exterior feature. See HOA approval for a metal roof.

Expect a written material warranty and clear installation details. Interlock aluminum siding carries a transferable 50-year limited warranty. Read the warranty document for what it covers and how a transfer works, and keep it with your house records.

For installation, the estimate should name the water-resistive barrier, the fasteners and their material, how windows, doors and roof-to-wall joints will be flashed, and how existing siding and any damaged sheathing will be handled. On the coast, confirm that fasteners and trim suit salt exposure.

Metal Roof NC, an authorized Interlock aluminum roofing dealer, installs Interlock aluminum wall cladding and metal siding as well as roofing, across the Triangle, Charlotte, the Triad and the coast. Workmanship on its installations is covered by the Metal Roof NC 5-Year Labor Warranty. A project-specific estimate before work begins will cover both the walls and the roof if you are doing both. See aluminum roofing, the warranties page and our service areas.