In New Zealand, where the prevailing winds carry corrosive salt-laden air many kilometres inland, ZINCALUME® offers the first line of defence. Zincalume® is an aluminium/zinc alloy coated steel that gives significantly longer service life than a galvanised coating for most roofing and cladding applications. The materials act in harmony with each other, combining the corrosion protection of aluminium with the sacrificial protection of zinc.

In the last 25 years, test sites from around the world have provided a wealth of information on the comparative performance of galvanised and Zincalume® coated steel products. Though corrosion rates vary according to the severity of conditions, Zincalume® steel coatings out-perform galvanised coatings in almost all environments. This is particularly true in marine environments where Zincalume® coated steel will provide a significantly longer service life than galvanised steel.

  • Category
    Metal Cladding, Metal Roofing

Zincalume® is a versatile product, ideal for roofing, wall claddings, gutters and downpipes, fences and garden sheds.

 Key Features:

A 55% aluminium and 45% zinc alloy coating that enhances corrosion resistance

Long-term corrosion resistance in many atmospheric conditions

Zincalume® coated steel has a finely spangled silvery matt finish.

Performance Attributes:

Zincalume® is an aluminium/zinc material coated to AS/NZS 2728 and therefore is consistent with the NZ Building Code for use in environment as described in Acceptable Solution E2/AS1 Table 20.


  • Steel substrate may be either G300 or G550 consistent with AS 1397:2011
  • Metallic coating is AZ 150 consistent with AS 1397:2011
  • Tolerances are consistent with the requirements of AS/NZS 1365:1996

Fire Resistance:

  • Zincalume® is rated as a Group 1-S material and has an average specific extinction area of 3.8m2/kg.

Rain Water Systems:

  •  Rainwater collected from roofs clad with products made from Zincalume® coated steel will comply with the provisions of NZBC G12.3.1, provided the water is not contaminated from other sources.
  • The first 25 mm of rainfall from a newly installed roof must be discarded before drinking water collection starts. Where a paint or paint system is applied to the roof, its suitability for the collection of drinking water must be established from the manufacturer.
Guidelines for Use

Zincalume® products are designed for use in moderate environments.

Limitations of Use:

Zincalume® is not recommended for the following applications:

  • Intensive animal shelters, where the build-up of alkaline fumes may occur
  • Swimming Pools, and other structures with continually wet internal environments
  • Buildings with harsh internal environments such as galvanising plants, tanneries and meat works
  • Fertiliser works
  • Embedded in concrete
  • In contact with soil, bark or similar
  • Geothermal areas
  • Culverts
  • Highly alkaline environments (eg cement manufacture)
  • Coolroom products

Before using Zincalume® products in these environments please consult us for a recommendation on 0800 697 833 or

Copper or brass pipes must not be allowed to discharge onto or come into contact with Zincalume® steel products. The use of other materials in proximity to Zincalume® products must be carefully considered – the COLORSTEEL® Incompatible Materials bulletin should be used as reference.


Zincalume® coated steel is readily paintable using good quality primers and water-based acrylic topcoats. Paint manufacturers' instructions should be followed. Dirt, grease and any loose materials must be cleaned off so the surface is clean and dry prior to the first coat being applied.

Handling & Storing:

The normal storage care, site cleanliness and installation procedures used for GALVSTEEL® products apply to Zincalume® steel products. Although passivation provides improved protection during storage, care should still be taken. If Zincalume® steel becomes wet during storage, the product should be immediately separated, wiped with a clean cloth and placed in a position where it can completely air dry.

Warranty and Maintenance


Zincalume® steel products are warranted in moderate environmental categories for roofing, wall cladding, spouting and fascia. Please refer to New Zealand Steel's Environmental Categories, Warranty and Product Maintenance Recommendations Brochure for further information.


All roofing and cladding products are subject to the cumulative effects of weather, dust and other deposits. Compared to galvanised steel, Zincalume® coated steel performs exceptionally well in areas not regularly washed by rainwater. However, as with any steel based product, regular washing of areas not naturally rain washed is essential to ensure that a satisfactory life is realised from the product.

Regular washing of steel products increases the durability by reducing attack from airborne salts and pollutants. Steel surfaces should be manually washed with water and a sponge or a soft nylon-bristled brush.

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COLORSTEEL® is made, tested and trusted for New Zealand conditions. We are inspired by the colours and landscapes that surround us and, in turn, we strive to create products that will inspire you. For more inspiration, visit

To learn more about the winning projects and professionals celebrated at our recent COLORSTEEL® Awards 2023, click here.

Our story started over 40 years ago when New Zealand Steel began making COLORSTEEL® roof and wall cladding products from New Zealand iron sand. It was a world first, and a feat that required imagination, ingenuity and sheer determination. 

These qualities have become COLORSTEEL® pillars - it’s who we are and how we work. 

For New Zealand:
We’re inspired by the landscape around us. From snow topped mountains to tussock grasslands, you’ll see New Zealand reflected in everything we create.

COLORSTEEL® products also undergo intense, long-term colour performance and exposure testing. So you can be sure they’re made and trusted for our conditions. We’re so confident in the durability of our products, we back them with robust warranties.

For you:
We’ve developed COLORSTEEL® products to meet the needs of New Zealanders. Whether it’s roofing your dream home, building a fence or cladding a warehouse– there’s a COLORSTEEL® solution for your project.

By combining beauty, durability and flexibility, we believe COLORSTEEL® is about more than just a steel solution - it’s about turning metal into magic and transforming the everyday.

For the environment:
All COLORSTEEL® solutions carry the Environmental Choice NZ licence which means they can contribute to the achievement of maximum points in Homestar and Green Star materials credits with NZ Green Building Council.