Metal Cladding Materials

A Low/Medium/High metal-weight label cannot establish whether an existing wall can carry new cladding. Shortlist by exposure and system, then obtain panel, stiffener, rail, bracket and flashing mass in kg/m² for the actual build-up.

Decision	Compare on this basis	Next check
Load-limited renovation	Complete system kg/m², at stated thickness and support layout	Structural capacity and attachment
Coastal or de-icing exposure	Exact alloy, coating and sheltered conditions	Manufacturer limits and cleaning
Living patina	Drainage and accepted colour change	Runoff onto adjacent materials
Painted architectural surface	Named finish and exposure terms	Maintenance and warranty scope

The metal behind a wall panel decides most of what the finished wall can do: weight per square meter, weathering, available finishes, cost, and maintenance. This cluster is the metal-selection layer of the metal wall coverings guide. It does not replace a system choice. The same aluminum coil can be a cassette, a composite skin, or a perforated screen.

Use this cluster after you know whether the wall is interior or exterior and whether it is a rainscreen skin, an insulated sandwich or a screen. Then pick the metal that can do that job in that climate.

How to read a material page

Each material guide follows the same structure so metals can be compared like-for-like: what the metal is, the panel forms it usually takes, strengths, limits, where it fits, and the specification traps that belong to that metal. Performance tables on those pages are orientation, not test reports. Product-specific and assembly-specific numbers still come from the manufacturer and the listed wall.

Industry context for aluminum sits with the Aluminum Association. Broader metal-wall practice sits with the Metal Construction Association.

The six metals this hub covers

Aluminum wall panels are the common architectural answer. Obtain mass per area for the selected thickness and complete system; a lighter skin does not establish the required subframe or renovation capacity. A natural oxide film plus PVDF, powder coat or anodizing covers most colour work. Softness and thermal movement are the usual limits. Aluminum is also the usual face metal for Metal Composite Material panels.

For bonded aluminum skins, the aluminum composite panels (ACP) guide separates core identity, NFPA 285 wall-assembly evidence and the routing details used to form returned edges.

Steel wall cladding is the economical structural skin. Ordinary carbon-steel exterior panels need a documented corrosion-protection system. Profile and support layout are part of the design of corrugated fields and insulated metal panel faces. Unprotected ordinary carbon steel is not the intended weathering finish here; purpose-made weathering steel is a separate alloy and exposure decision, described below.

Stainless steel wall panels are an alloy and finish decision. Grade, surface and cleaning decide whether the wall stays useful in kitchens, transit interiors or chlorides. “Stainless” on a drawing without an alloy is not a specification.

Corten steel cladding develops a rust patina that becomes the finish. Runoff staining on adjacent stone, glass and paving is the project risk. Corten is a detailing system. It is the wrong choice when the client wants a rust colour without brown water.

Zinc wall cladding weathers to a gray patina and wants ventilation, compatible flashings and slopes that drain. Pre-weathered zinc is often specified to avoid a long, uneven bright period. Zinc fails when it is treated like coated aluminum and sealed against the backup.

Copper wall cladding moves from bright metal through brown toward green. Runoff and oil canning on flat bright faces need design attention. Copper is a signature metal. It is a poor substitute for a painted panel when the only requirement is “warm metal.”

What the metal does not decide

Material choice does not decide drainage. A zinc rainscreen and a zinc face-sealed box are different walls. Material choice does not decide fire classification of a composite or insulated product; the core and the listed assembly do. Material choice does not decide oil canning by itself; panel width, stiffening and gloss do.

If the remaining argument is format, open the systems hub. If it is climate versus interior accent, open the applications hub. If two metals remain, open aluminum versus steel or the matching comparison.

Climate and couples

Coastal air, de-icing salt and industrial fallout change the shortlist. Check the actual alloy, coating and sheltered exposure rather than treating a metal family as a corrosion approval. Cut edges, weep paths and fastener metals still have to be written. Dissimilar metals in wet contact are a corrosion problem, not a style problem.

Living-patina metals need a place for water to go and a surface that is allowed to change. If the adjacent materials cannot accept stain, do not specify corten or untreated copper above them.

Which metals suit coastal or polluted sites?

Salt exposure needs a product-specific check; a family name alone is insufficient.

• Aluminum: confirm the exact alloy, temper, finish and fasteners for the exposure. A generic 5000-series designation does not approve every coastal assembly (aluminum guide).
• Coated steel: BlueScope’s public Steel walling products — selection guide distinguishes its walling products by marine environment and unwashed conditions. Use the actual coating product’s written limits and warranty for the site; these Australian product conditions are not universal setback rules (steel guide).
• Stainless: ASSDA’s Tea Staining guidance treats 316 as a coastal starting point and calls for higher grades in severe, splash or unwashed conditions. Finish, drainage and cleaning still matter (stainless guide).
• Weathering steel: assess whether the site and detail allow the intended patina; do not substitute it for protected ordinary carbon steel or assume suitability in persistent salt or wet conditions (weathering-steel guide). The 30 mm ventilation gap, the 18 to 36 month window, and the 1989 chloride lines are on the weathering-steel numbers page.
• Zinc and copper: check reverse-face drainage, compatibility and runoff for the named product (zinc and copper).

Record sheltered surfaces and cleaning access alongside the exposure; see metal cladding corrosion.

Material selection checklist

Use this before you compare quotes or samples. Each item is something a specification can state and a bidder can price.

1. Exposure written down: distance to salt water, de-icing spray at grade, industrial air, and the sheltered faces that will not be rain-washed.
2. System chosen first: rainscreen skin, insulated panel, composite panel or screen. The metal has to suit that format.
3. Metal named precisely: alloy and temper for aluminum, metallic coating type for steel, grade for stainless. “Galvanized” or “stainless” on its own specifies nothing.
4. Finish and colour class stated: coating system and its warranty terms for painted metals, or an accepted colour range for zinc, copper and corten patinas.
5. Couples and runoff drawn: isolation wherever dissimilar metals stay wet, plus drip edges and catchment below copper and corten.
6. Maintenance and cost horizon agreed: washing, inspection and touch-up rules, priced as an installed system rather than a sheet price.

The comparison table below the article text summarizes the six metals against these checks. Each row comes from that metal’s own guide, which carries the detail and the sources.

Cost position, not a quote

Relative cost on this site is a position, not a bid. Coated steel is usually the lowest metal line. Aluminum sits above it. Stainless, zinc and copper sit higher, and labour plus custom work can erase the metal difference. Read metal cladding cost before treating a coil price as the project price.

How to use this hub

1. Name exposure and drainage on the applications and systems hubs.
2. Open the one or two material guides that can survive that climate.
3. Write finish class, isolation and maintenance, not only the metal name.
4. Return to the metal wall coverings guide if the four-question sequence was skipped.