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Colorbond Granny Flats – What You Need to Know Before using Colorbond

When it comes to a choosing the materials for your granny flat – are Colorbond granny flats a popular choice?


Colorbond is a metal roofing that is manufactured by Bluescope Steel. It is an extremely popular choice to use as a material for a roof for both home owners and the builders of secondary dwellings alike. And can also now be used for walls and any other exterior coverings


Today, I will cover:


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  • Different roofs for a granny flat.
  • Will Colorbond last longer than regular roof tiles?
  • Should you double coat a Colorbond roof?
  • What advice does Colorbond give for living by the ocean?
  • What other Colorbond products are used for granny flats?


So, let’s get started…


Different Roofs for a Granny Flat


Below are your common options of different roofs for a granny flat.


Pitched (Using Trusses):


Also known as a gable/gabled roof, pitched roofs are one of the more common types of roofs.


A pitched roof with matching wall cladding Source: Colorbond


As implied by the name, a pitched roof has an unmistakable pitch in the centre, where the two proportional roof panels join.


The benefits of pitched roofs are that they:



Skillion (Using Rafters):


Also known as a shed roof or lean-to-roof, a skillion roof is technically still a pitched roof. However, where they vary from your standard pitched roof as instead of being triangular in shape, they only have one roof surface that is raised at an angle.


Skillion roofs are very popular in modern designs, due to their unique profile and architectural style. So, they are a great choice when building a granny flat.


skillion roof granny flats

Skillion roofs can work in different angles. Source: Maxable Space 


Of course the common choice is one angle for a skillion roof over a standand rectangular shaped granny flat. However it doesn’t mean you can work with your land to add “gaps” where light can be let in such as the example above.


Wall Cladding with Colorbond


Over the last few years, wall cladding using Colorbond products has become increasingly popular.


I tracked down a great Pinterest Board (which you can see by clicking the image below) to inspire you on using Colorbond as cladding.



Even though Colorbond is commonly thought of for roofs, there are some great mix of materials you can use to make your granny flat really stand out.


Will Colorbond Last Longer Than Regular Roof Tiles?


Your choice for roof covering for a granny flat is generally either concrete tiles or Colorbond. So, does one last longer than the other?


Let’s begin by discussing whether Colorbond is better than regular roof tiles. So, we’ll explore the pros and cons of both.


Colorbond Advantages:


  • Weather-resistant – This steel that has been coated and bonded is perfect for withstanding the harsh weather we have in Australia. It can stand up against the highest winds, unlike some roof tiles.
  • Many colour choices – Colorbond roofing is made in an abundance of unique colours, so you can always choose a colour that matches your taste and style.
  • Highly energy-efficient – Colorbond is manufactured out of corrugated metal, which is extremely reflective. In the summer, the roof will help keep the granny flat cool inside by reflecting the sun away.


Colorbond Disadvantages:


  • The colour of the roof will fade – In 10-20 years, the bonded paint finish that Colorbond uses in their roofing will fade, and you will need to repaint it, to bring back its’ colour.
  • The sound of the rain will be louder – In comparison to a tiled roof, the rain will be more noisy with a Colorbond roof.


Concrete tile advantages:


  • Energy efficient – Because the tiles are very thick, they will help keep the granny flat warm during winter and cool during summer, as the heat loss is reduced through the structure of your roof. (PLEASE LINK TO NEW ARTICLE)


Concrete tile disadvantages:


  • Heaviness – Concrete tiles are heavy, and as a result your roofing structure may need to be reinforced to support their weight.
  • Cost – Concrete tiles generally cost quite a bit more than Colorbond roofing.


However, we still have not discussed the main question – will Colorbond last longer than regular roof tiles?


The answer is no. Even in our harsh Australian climate, you can expect concrete tiles to last a minimum of 50 years. Colorbond roofing will generally last roughly 50 years before it needs to be replaced.


So, tile roofing is the most long-lasting roofing material that we have available.


If you are still not sure what is right for you and your granny flat, you can always speak to your designer and ask their advice.


Should You Double Coat a Colorbond Roof


As this highly informative article shows, your location may affect the Colorbond steel.


Therefore, more special grades of steel are designed to suit more challenging environments, such as those by the ocean, those susceptible to industrial or chemical fumes, or those that undergo cyclonic circumstances.


It is also strongly recommended in these same areas to double coat (with paint) your Colorbond steel – this will help it last longer under these more extreme conditions.


For roofing, I suggest that you double coat a Colorbond roof if you live:


  • Within 100 to 200 metres from the ocean and its’ breaking surf, or anywhere there is still a smell of salt or salt spray in the air.
  • Within 100 to 200 metres from the cause of industrial secretions (i.e. fumes or particulate matter).
  • In an area that endures cyclonic conditions. For more information on the requirements of these regions, it is recommended that you get advice from your nearest roofing manufacturer.


What Advice Does Colorbond Give You for Living by the Ocean?


Following on from the above, not only is it highly important you choose the correct type of Colorbond steel for your roof if you live in a coastal area – that is:


  • Colorbond Stainless steel within 100m from the ocean, or
  • Colorbond Ultra steel within 100m to 200m from the ocean.


It is also important that you use the correct screws and fasteners to fix the roof. Using the improper roof screws could lead to your roof to failing due to speeding up corrosion, as it can cause:


  • Galvanic corrosion – The incorrect screw might bring about a galvanic reaction with your roofing material, accelerating the process of corrosion multiple times.
  • An accumulation of detritus around sides of screws that have been badly designed – This means the water will intensify around the screws. It may include conductive salts, stimulating corrosion.
  • The dampness around/underneath the screw head lengthens the amount of time the steel remains wet – Making corrosion speed up.
  • Water to enter the roof cavity – It may lead in underneath imperfectly constructed or damaged screw heads or washers.


So, if you live by the ocean, it is important that you invest in anti-corrosion screws and fasteners. If you try to save money by using inadequate quality screws, you are only setting yourself up for a disaster. 


Whereas anti-corrosive screws will help you to prevent premature corrosion, and costly, unpleasant damage to your Colorbond roof. 


What Other Colorbond Products Are Used for Granny Flats?


Other Colorbond products that are commonly used for granny flats are gutters, fascia and downpipes.


You can use these to match or enhance the style and colour of your roof and other building materials, as you can choose from:


  • Twenty-two (22) different colours.
  • An extensive range of designs, sizes, and shapes. 


A selection of gutters is available to view on their SteelSelect website.


A metal fabricator will also take Colorbond products and machine them, using giant machines, to make any shape you want or need.


For example, if you want to cap-off something, such as hand-railing for stairs, they can create this.




A Colorbond roof is a steel roof with a bonded paint finish. It is an extremely popular type of roof for a granny flat.


Though it is not as long-lasting as your other choice for roofing (that is, concrete tiling), it has many other advantages.


You must just ensure to treat it properly if you live in a more difficult location, (i.e. near the ocean). 


I hope this has helped you decide what is the right type of roofing for you. 


If so, and you are ready to start building your granny flat now, feel free to see how I went when I built my granny flat.