Aluminium Slat Roller Doors vs Steel Roller Doors for NZ Homes

An aluminium slat curtain is built from individual extruded aluminium profiles, interlocked to form the rolling curtain. A steel curtain is roll-formed from a single continuous strip of Colorsteel®-coated steel.

Base metal, forming method, weight, and long-term wear all trace back to that one choice: extruded and interlocked versus roll-formed and continuous. The two products are built differently from the start, and that difference shows up in every comparison below.

Aluminium is a non-ferrous metal. It has no rust pathway, so it doesn’t depend on a coating staying intact to resist corrosion. A steel curtain relies on its Colorsteel® coating system to do that job, and that coating comes in different specifications for different exposure levels, from standard suburban environments through to more severe coastal conditions.

The closer a property sits to open water, harbour edges, exposed coastline, or areas that get regular salt-laden wind, the more that protective margin matters. Inland and typical suburban properties are well served by a standard Colorsteel® specification. Properties right on the coast usually suit aluminium better, since it avoids the corrosion question rather than managing it with a heavier coating.

Coastal exposure isn’t just straight-line distance from the sea. Wind direction, elevation, and how sheltered a site is all play a part. Windsor Doors’ site measure confirms the right specification for your property, rather than relying on a rough estimate.

Windsor Doors’ free site measure and quote confirm the right material for your address. Distance from the coast alone isn’t a reliable guide.

Aluminium slats are extruded rather than roll-formed, so they’re generally lighter per square metre than an equivalent steel curtain. A lighter coil reduces the load the motor has to lift and hold, which can mean a lighter-duty compliant drive unit works for the same size opening.

A lighter curtain doesn’t just lift more easily. It changes the motor size the door needs, so automation cost isn’t necessarily the same across both materials. Your Windsor Doors quote will confirm the exact curtain gauge and motor specification, since it depends on door size and configuration.

Aluminium slat roller doors generally cost more than steel curtain roller doors because the curtain uses individual interlocking components. Extruded aluminium profiles are more expensive to produce than roll-formed steel strip, while installation labour is broadly comparable for both options. Overall, you can typically expect an additional cost of around $1,000 to $3,000.

Steel is a sound, cost-effective choice if budget is the main constraint and your property isn’t in a high-exposure coastal position. For an exact comparison on your specific opening, Windsor Doors can confirm the real numbers with a free quote.

Steel has a higher yield strength than aluminium at an equivalent gauge, so it resists localised impact better, whether it's a bumper clipping the bottom panel, hail, or a stray basketball. Aluminium is softer and more likely to dent permanently from the same knock.

The properties that make aluminium corrosion-resistant, being a softer, more workable metal, also mean it dents more easily than steel. Which one suits you better depends on whether tight vehicle clearance or salt exposure is the bigger risk for your garage.

Both standard aluminium slat and standard steel roller door curtains are single-skin, uninsulated products. Neither meaningfully slows heat transfer. If keeping the garage warmer or cooler matters because it doubles as a workshop, gym, or living space, a roller door isn’t the right product to compare in the first place.

Auckland’s relatively mild coastal climate means an uninsulated roller door is adequate for a garage used purely for parking and storage.

This page covers standard aluminium slat and steel roller door curtains. If insulation is a priority, consider an insulated sectional garage door instead.

Exposure varies suburb to suburb across Auckland, sometimes within a few streets. Waterfront and harbour-edge locations, such as Devonport, Hobsonville’s waterfront stretch, or Māngere Bridge, are more exposed, and aluminium is typically the recommended specification there. Move further inland into typical suburban Auckland, and a standard Colorsteel® steel curtain generally suits.

Windsor Doors assesses each property individually, factoring in proximity to open water, prevailing wind exposure, and site conditions, and confirms the right material as part of the site measure.

Colorsteel® coating specifications, and where aluminium becomes the recommended material, are confirmed at your Windsor Doors site measure, which accounts for more than the straight-line distance to the coast.

AS/NZS 4505:2012 is the core joint Australian/New Zealand standard governing the design, construction, and installation of garage doors. It covers structural loads, wind pressure ratings, corrosion resistance, and door mechanisms and locking devices, and none of it depends on curtain material. It applies to the door as a structure, not to whichever metal the curtain is made from.

Motorised roller doors also need to meet AS/NZS 60335.2.95, the companion standard covering the safety of powered garage door drives: entrapment protection, auto-reverse function, and a manual release for power failure. That standard applies to the drive and safety system, so it applies the same way whether you choose aluminium slat or steel.

Compliance with AS/NZS 4505:2012 and, for powered doors, AS/NZS 60335.2.95, is mandatory in New Zealand. Speak with your installer for the details relevant to your setup.

When deciding, ask yourself 3 key questions: Does your property need protection from salt exposure? What is your budget? And what do you need your door to deliver in terms of appearance, durability, and performance?

Aluminium slats suit homes close to open water or in exposed coastal positions, or anyone who wants corrosion-free, low-maintenance performance over steel’s lower upfront cost. Steel suits a typical inland or suburban location, a tighter budget, or a garage where dent resistance from vehicle contact matters more than corrosion exposure.

Windsor Doors’ site measure turns this general framework into a confirmed recommendation for your home, checking exposure, opening size, and automation needs before anything is set in stone.

From there, you can view finish and colour options in person at Windsor Doors’ Hamilton showroom, or through the virtual showroom if that’s more convenient.

For an exact specification and price for your home, contact Windsor Doors today. We’ll help you choose the right roller door for your needs.