If you are replacing an ageing metal roof or choosing roofing for a new home, there is a good chance you will come across two familiar Australian names: ZINCALUME® steel and COLORBOND® steel.

Both are widely used roofing materials made for Australian conditions, but they are not quite the same. The biggest difference is that ZINCALUME® has a distinctive unpainted metallic finish, while COLORBOND® steel adds a durable pre-painted finish and gives homeowners a much wider choice of colours.

That does not necessarily make one product better than the other.

The right choice depends on your home’s design, location, exposure, budget and the look you want to achieve.

For homeowners considering a roof replacement or re-roof, here is what is worth knowing before deciding between COLORBOND® and ZINCALUME® roofing.

What is ZINCALUME® roofing?

ZINCALUME® steel is an Australian-made steel product manufactured by BlueScope. Rather than relying on ordinary galvanised zinc protection, the steel is coated with an aluminium, zinc and magnesium alloy incorporating BlueScope’s Activate® technology.

The coating is designed to protect the underlying steel against corrosion while retaining the familiar silver-grey metallic appearance associated with ZINCALUME® roofing.

It is commonly formed into roofing and walling profiles and is used across residential, commercial and agricultural buildings.

You can read more about the material directly from BlueScope’s ZINCALUME® product information.

What is COLORBOND® roofing?

COLORBOND® steel is also manufactured by BlueScope, but it includes additional protective and decorative coating layers.

Rather than leaving the metallic surface exposed, COLORBOND® steel has a pre-painted finish incorporating pre-treatment, primer and a baked-on topcoat. This provides the familiar coloured finish seen on homes throughout Australia.

COLORBOND® is available in a wide range of colours and finishes, making it particularly popular when the appearance of the roof forms an important part of the home’s overall design.

Most of the core COLORBOND® colour range also incorporates Thermatech® solar reflectance technology, which is designed to reflect more of the sun’s heat on hot, sunny days. Actual thermal performance still depends on factors such as the roof colour, insulation, building design and location.

More information is available from COLORBOND® steel.

ZINCALUME vs COLORBOND at a glance

Pros of ZINCALUME® roofing

1. Proven corrosion protection

ZINCALUME® steel is designed specifically to protect the underlying steel from corrosion using its aluminium/zinc/magnesium alloy coating.

BlueScope introduced the current generation of ZINCALUME® steel with Activate® technology after extensive research and testing, making it a well-established choice for Australian roofing.

2. A clean metallic appearance

Some homeowners simply prefer the silver-grey appearance of unpainted metal roofing.

It can work particularly well on sheds, rural properties, contemporary homes and buildings where a simple metallic roof complements the architecture.

3. No colour decision required

Choosing a roof colour can have a surprisingly large impact on the appearance of a home.

If you prefer the traditional metallic appearance, ZINCALUME® removes that decision entirely.

4. Recyclable steel

Steel roofing can be recovered and recycled at the end of its useful life, making both ZINCALUME® and COLORBOND® worth considering for homeowners looking at the longer-term lifecycle of building materials.

Potential drawbacks of ZINCALUME® roofing

Limited aesthetic choice

The most obvious limitation is also part of its appeal.

ZINCALUME® gives you a metallic finish rather than a palette of colours. If you want the roof to match a particular fascia, gutter, cladding or exterior colour scheme, COLORBOND® generally provides much greater design flexibility.

The appearance will naturally weather

ZINCALUME® is an unpainted steel product, so homeowners should expect its metallic appearance to weather naturally rather than retain the appearance of a painted architectural finish.

That is not necessarily a disadvantage, but it should be considered when choosing a roof primarily for visual reasons.

Pros of COLORBOND® roofing

1. Extensive colour choice

This is probably the most obvious advantage for residential properties.

COLORBOND® is available in numerous colours designed to complement Australian homes, landscapes and building styles.

This makes it much easier to coordinate the roof with gutters, fascia, walls, windows and other exterior finishes.

2. A multi-layer protective coating system

COLORBOND® roofing does not simply consist of ordinary steel with paint applied to the outside.

BlueScope manufactures COLORBOND® steel with multiple protective layers, including a corrosion-resistant metallic coating, pre-treatment, primer and a durable baked-on topcoat.

The result is a roofing material designed to cope with Australia’s demanding conditions while maintaining an architectural painted finish.

3. Solar reflectance technology

The core COLORBOND® range in Classic and Matt finishes incorporates Thermatech® solar reflectance technology in most colours.

It is designed to reflect more of the sun’s heat on hot, sunny days. However, homeowners should remember that roof colour is only one part of thermal performance.

Insulation, ventilation, building orientation and the design of the home also matter.

4. Greater architectural flexibility

For many homeowners, the roof is one of the largest visible surfaces of the house.

Choosing the right colour can dramatically change the appearance of the entire property, particularly when completing a major renovation or replacing an old roof.

Potential drawbacks of COLORBOND® roofing

More choices to make

The larger colour range is an advantage, but it also means homeowners need to think more carefully about the final look.

A roof is a long-term decision, so it is worth considering how the chosen colour works with the rest of the home rather than selecting it from a small sample alone.

Not every COLORBOND® product suits every environment

This is particularly important in coastal Queensland.

Being made from COLORBOND® steel does not automatically mean a particular product is suitable for every coastal or corrosive location.

BlueScope and LYSAGHT offer different material specifications for different environments. For example, COLORBOND® Ultra steel is designed for more severe coastal and industrial environments where additional corrosion protection may be required.

If your home is close to the ocean, the appropriate material should therefore be selected according to the property’s actual exposure rather than simply choosing a colour.

BlueScope’s material selection guidance provides further information about choosing materials for different environments.

Is COLORBOND® better than ZINCALUME®?

Not automatically.

For most homeowners, the decision comes down to appearance, location and what they expect from the finished roof.

If you want a wide colour selection and a roof that forms part of the home’s overall exterior design, COLORBOND® is usually the more obvious choice.

If you like the classic metallic appearance of unpainted steel and do not need a coloured finish, ZINCALUME® can be an excellent alternative.

Both products are designed for long-term roofing applications. What matters just as much as the material itself is whether the correct product specification has been selected for the property and whether the roof has been installed correctly.

What about homes near the coast?

For homeowners around coastal parts of Queensland, this question deserves more attention than simply comparing COLORBOND® and ZINCALUME® by price or appearance.

Salt, moisture and proximity to breaking surf can create much more aggressive corrosion conditions than a property further inland.

Different BlueScope roofing products are designed for different environments, and there are circumstances where a higher-grade product such as COLORBOND® Ultra may be more appropriate.

That means a roof that works perfectly well on one property may not necessarily be the correct specification for another home only a relatively short distance away.

If you are replacing a roof around Bundaberg, Agnes Water, Gladstone, Hervey Bay or another coastal area, ask your roofer specifically whether the proposed material is suitable for the property’s exposure.

Does roof colour make a difference?

Yes, although not always in the way homeowners expect.

The colour of a roof can influence both the appearance of the house and the amount of solar energy the roof absorbs.

Lighter roof colours generally reflect more solar energy than darker colours, although the overall thermal performance of the home also depends heavily on insulation, roof design, ventilation and other building characteristics.

COLORBOND® gives homeowners much greater control over this decision because of its colour range.

When choosing a colour, consider:

• The colour of the exterior walls
• Existing or proposed gutters and fascia
• Window and door colours
• The architectural style of the home
• Surrounding homes and streetscape
• How dark or light you want the overall exterior to appear
• The home’s insulation and thermal design

Should you replace your gutters when replacing the roof?

Not necessarily, but a re-roof is an excellent time to assess them.

If the existing gutters are still in good condition and work effectively, replacing them simply because the roof is being replaced may not be necessary.

However, if they are rusting, leaking, poorly aligned, undersized or nearing the end of their useful life, addressing them while the roof is being replaced can make practical sense.

It also gives homeowners the opportunity to coordinate the gutter and roof colours when choosing COLORBOND® finishes.

Pitch-Perfect Roofers provides both guttering and roof plumbing as part of our roofing services.

What else should be checked during a roof replacement?

A new roof is only one part of the roofing system.

Before re-roofing, an experienced roofer should assess the condition of the existing roof and related components rather than simply removing the old sheets and replacing them.

Depending on the property, this can include checking:

• The condition of the existing roof structure
• Roof battens and supporting components
• Flashing and roof penetrations
• Gutters and drainage
• Existing insulation
• Signs of previous water entry
• Corrosion or deterioration around problem areas
• Whether the proposed roofing material is appropriate for the property’s location and exposure

This is particularly important when replacing an older roof where previous repairs or hidden deterioration may only become obvious once work begins.

What warranties are available?

Both COLORBOND® and ZINCALUME® steel are backed by BlueScope warranties where the product, application and installation meet the relevant eligibility requirements.

There is not one universal warranty period that applies to every roof.

Warranty eligibility and duration can depend on factors such as the particular product, application, building location and environmental exposure.

Homeowners considering a new metal roof should therefore ask which BlueScope warranty applies to their specific project rather than relying on a general warranty claim.

You can find further information through BlueScope’s COLORBOND® warranty information.

So, should you choose COLORBOND® or ZINCALUME®?

For many residential homes, COLORBOND® is attractive because it combines durable steel roofing with a broad choice of colours and finishes.

ZINCALUME® remains a strong option for homeowners who prefer its traditional metallic appearance and do not need the additional design flexibility of a pre-painted finish.

The better question is therefore not simply:

“Is COLORBOND® or ZINCALUME® better?”

It is:

“Which roofing material is better suited to this particular home?”

That decision should take into account the condition and design of the existing roof, the property’s location, local exposure, the look you want to achieve and the appropriate material specification.

Frequently asked questions about COLORBOND® and ZINCALUME® roofing

Planning a metal roof replacement?

If your existing roof is ageing, leaking or showing signs of corrosion, choosing the material is only one part of the decision.

Pitch-Perfect Roofers can assess the condition of your existing roof, explain whether repair or replacement makes the most sense, and help you choose an appropriate roofing material for your home and location.

With more than 20 years of roofing experience across regional Queensland, we work with homeowners throughout Bundaberg and surrounding regions including Gladstone, Hervey Bay, Maryborough, Agnes Water and Rockhampton.

Request a free roofing quote or call Pitch-Perfect Roofers on 0412 856 623 to discuss your roof replacement.