Metal Roofing, what is best

by | Jan 15, 2022

Due to Perth’s naturally harsh climate, I thought we could discuss some key differences between ZINCALUME® and Colorbond® steel so you can make a more informed decision when deciding on the material you choose for your metal roofing project. There is obviously no debating Colorbond® and ZINCALUME® are top-quality true-blue metal roofing materials. Produced by Australia’s own Bluescope steel. So, there is no surprise they are both going to be quality Steel Roofing options.

Colorbond® or ZINCALUME® Coating


Colorbond® metal roofing comes already coated.  Colorbond® metal roofing goes through a process known as powder coating.

Powder coating is a free-flowing dry powder that is used to coat the Colorbond® roof sheets.

Unlike traditional liquid paint, applied using an evaporating solvent, powder coating is usually applied electrostatically to the Colorbond® metal roof sheeting and then will be placed under heat or ultraviolet light to cure.

The powder is generally either a thermoplastic or a thermoset polymer. Which will create a hard finish that is consistently stronger than conventional and other methods of paint for metal roofing. Therefore, giving your Colorbond® roof sheets that strong gruff Australian exterior we have come to love in Perth.


ZINCALUME® on the other hand ZINCALUME® steel is regarded as more of a premium steel product with a metallic coating. That coating is believed to have a consistency of aluminium around 55%, zinc at 43.5% and silicon at 1.5%. This is said to give ZINCALUME® an average life span of up to four times that of galvanized steel.

An interesting fact: ZINCALUME® is actually the base material in both Colorbond® roofing and ZINCALUME® roofing. Although the ZINCALUME® will not give you as many colour options.

Both coatings discussed essentially play the same role which is to protect the base metal roofing sheets from the harsh Perth elements and prevent corrosion.

Colorbond® Vs   ZINCALUME® Pros & Cons

Positives of Colorbond Metal Roofing:

  1. Choosing Colorbond® metal roofing gives you a full range of 22 colours to choose from. Whether your home is historic or modern with sleek and stylish architecture Colorbond® will have a colour that compliments your design.
  2. Secondly, Colorbond® roofing is termite resistant, non-combustible and obviously when installed by the professionals at Powerdrive Roofing is completely weather tight. Colorbond® roofing has a long life expectancy even in Perth’s harsh climate.
    *(Bluescope warranty covers up to 30 years against corrosion to perforation. Also up to 12 years against paint flake & peel (ie delamination) on application to Bluescope at the time of installation.)
  3. Colorbond® Roof sheeting can be rolled on site. With the use of Colorbond® metal mobile roll forming we can have sheets made to measure on-site in lengths of up to 100 meters. Gone are the days of overlaps or lap joints, therefore eliminating other potential water ingress areas.
  4. As already touched upon Colorbond® metal roof sheeting due to the powder coating has great corrosion resistance. Providing your roof Plumbers know the correct tek screws to use with the Colorbond® so there is no reaction between contrasting metals.

Negatives of Colorbond® Roofing

  1. We have covered Colorbond® and their 22-colour pallet. However. Certain ranges in the Colorbond® metal roofing have been known to fade or deteriorate after only 10 to 15 years.
    When the colour fades or breaks down on your Colorbond® roof. It can look very unsightly and leave you with only one option. Roof Restoration more so roof painting when it is a metal roof, one would hope there is no other maintenance required after only 10 years.
  2. When comparing the price, the Colorbond® checks in at almost double the price when comparing the (BMT) it’s not some cool sandwich, it is the base metal thickness. So, it is food for thought I suppose, yep, I did it, I snuck in a dad joke, something had to break it up a bit.
  3. This sort of goes back to the colour fade. If there is A damaged Colorbond® metal roofing sheet and it is required to be changed, it will be next to impossible to colour match even if the roof is only a year or two old.
  4. If you are wanting to reside in one of Perth’s fantastic coastal suburbs you don’t have the luxury of using standard Colorbond®. Due to the salty air and highly corrosive nature of seaside living you will need to upgrade to Colorbond® Ultra, this is around triple the price of the traditional ZINCALUME® metal roofing.

Positives of Zincalume:

  1. During Perth’s hot summers with the sun beating down we are looking for heat reflective qualities.
    Heat reflective qualities are what we find in ZINCALUME® metal roofing.
    Couple that with a couple of Whirly birds and you cold almost cool your beers in the roof. Ok maybe not, but you get where I’m going with this.
  2. roof sheets on average are around half the price of Colorbond® roof sheets. So, you can get the roof replacement you know you need and have enough left over for that boat you have had your eye on.
  3. Even in extreme heat ZINCALUME® has second to none corrosion resistance. It really is made to cope with the Perth 40-degree scorchers.
  4. ZINCALUME® has that hard surface we have come to know which gives it the abrasion resistant quality we sometimes wish our kids had.
  5. Flexibility. The flexibility of the ZINCALUME® metal roof sheets make it a godsend to work with as a roofer. It follows any lines the roof carpenters can lay out for us and makes it a lot easier to work with.

Negatives of ZINCALUME® Metal Roofing:

  1. One of the positives of ZINCALUME® can also be one of its negatives. You can become the neighbour from hell. If the sun catches your roof at the wrong angles throughout the day.
    Unless of course the neighbour is keen on a tan, then you can start charging for the service.
  2. standard aluminium colour can be a disadvantage. It does not have the powder coating that Colorbond® has. It really means the option of ZINCALUME® leaves you with the choice of only one colour.
  3. Essentially making ZINCALUME® a product that cannot be tailored to your home’s style in the way the Colorbond® 22 colour pallet can.  The shiny metal roof can sometimes outshine the rest of your home. As a roofer we love the fact our work stands out, but not if it cheapens the look of the rest of the home.

Perth Town Hall New Roof Zincalume or Colorbond Roofing?

The Perth Town Hall, situated on the corner of Hay and Barrack streets in Perth, Western Australia, is the only town hall built by convicts in Australia. Upon completion, it was the tallest structure in Perth. Is it time for the Perth town hall to get a Roof Replacement? If so what do you think they should go for now that you are better informed? Colorbond® Metal Roofing or ZINCALUME® Metal Roofing?

*(Bluescope warranty subject to change and to be discussed with Bluescope, was correct information at the time of writing)

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