Get the best possible roof over your head with this comprehensive guide to roofing in Australia.
Choosing a roof can be a complicated and difficult task. From the look and colour of the roofing material to its durability, ability to withstand local weather conditions and cost, there’s a whole lot you need to consider to find the perfect roof for your home.
Let’s take a look at the materials available and the factors you need to consider to put a roof over your head.
What to consider when choosing a roof
Your choice of roofing material will be influenced by a wide range of factors, including:
- Weather conditions. Do you live in a hot or cold climate? Will the roof need to withstand severe storms, snow and other extreme weather conditions? If you live in a bushfire area, does it have a high fire rating?
- Look. Does the roof complement the style of the house and the surrounding area?
- Weight. Can the roof be safely supported by the house?
- Slope. Does it have an adequate slope to stop rainwater or snow pooling on top? Or would you like a flatter slope to maximise internal height in your home?
- Durability. How long will the roof last? What will it require in terms of regular maintenance?
- Insulation. Will your roof offer adequate insulation from heat and noise?
- Environment. Is the roofing material eco-friendly?
- The law. Does the roof meet all the requirements imposed by local building codes and regulations?
- Cost. Does your budget cover the cost of the roofing material you are considering?
There are several choices available when deciding on a roof for your home. Each option has its own pros and cons which need to be carefully considered before you make your final decision.
While it’s possible to find metal roofs made from materials such as tin, most modern Australian metal roofs are made from steel, which is durable, long-lasting and affordable, and therefore a popular choice. It’s also available in a wide range of colours.
Most metal roofs are installed in large, corrugated sheets which are available in a wide range of profiles, including galvanised iron, copper and zinc. There are also steel composites such as Zincalume, which is a combination of zinc and aluminium, and even metal tiles.
The main downsides of metal roofing are that it can cost more to install upfront, and it doesn’t offer as much heat and noise insulation as other materials available.
Costs vary widely depending on the type of steel selected. For example, galvanised steel can cost around $20 per linear metre, while Zincalume can range from $15 to $30 per lineal metre (not including installation). With installation costs included, you can typically expect to pay around $50 to $70 per square metre for metal roofing.
Tiles are available in a range of materials and profiles:
- Terracotta. A natural clay product, terracotta is strong but relatively lightweight. It looks great and is quite durable, and it comes in a range of colours and profiles, making it a popular roofing choice. However, terracotta is far from the cheapest roofing option available.
- Concrete. Cheaper than terracotta, concrete tiles look very similar in profile to terracotta tiles and are made from sand and cement. However, they’re more porous than terracotta and are likely to fade more quickly.
- Slate. Natural slate tiles are one of the most durable roofing materials and can actually increase the value of a property. However, they’re also quite expensive, and repair jobs on slate roofs can be tricky.
- Synthetic. Synthetic slate tiles are cheaper and lighter than natural slate but can be used to create a similar look.
Roof tiling installation costs typically range up to $130 per square metre, slate being the most expensive option to install. Concrete tiles cost around $40 to $60 per square metre, while terracotta tiles are usually priced between $80 and $110. Slate tiles can cost up to $500 per square metre.
Similar to tiles, roof shingles are manufactured as individual units. They most commonly come in asphalt, wood or slate, and are laid on your roof in an overlapping pattern to keep out moisture.
- Asphalt shingles are affordable and quite easy to install, and are resistant to fire, hail and rain. However, the metal elements that hold them together need regular maintenance.
- Wood shingles are durable, stand up well to a variety of weather conditions and also look great. However, they’re a more expensive option than asphalt and there’s the added risk of termites and fire damage.
- Slate shingles are durable, sturdy options, but their heavy weight makes them difficult to install. They can only be used on buildings properly equipped to handle the load.
Slate shingles are often selected for use in alpine areas, but wood and asphalt shingles are fairly rare in Australia. Contact a supplier to get an idea of how much they cost.
You also need to think about what insulation your roof will need. Insulation is essential with metal roofs to keep out heat and noise, and is fitted between the roof battens and the roof sheets. Insulation is often made from glass wool fibres backed by aluminium, but sheep’s wool, stone wool and polyester are also used. The thermal resistance of insulation is expressed as an R-value, and the higher the figure, the better its insulating properties. A nine-square-metre pack of glass wool insulation batts costs around $60, while sheep’s wool and polyester are more expensive. Installation costs begin at around $30 an hour.
Another option is to clad your roof with a so-called “cool roof” surface such as white vinyl, or use solar reflective paints to improve its insulating properties. Some modern homes even opt for a “green roof” turning the roof into a space to grow plants which absorb the sun’s solar energy.
Flashing and sarking
Roof flashing is designed to ensure that rain and other moisture are kept out of your home. There is a range of flashing options available, but they usually take the form of solid sheets or malleable membranes, and are used wherever there might be a gap that water could seep through, such as around ventilation outlets, windows and where the roof meets the walls.
Aluminium, copper, galvanised steel, stainless steel, zinc alloy and synthetic products can all be used for flashing. As the availability, costs and suitability of each differs per state and per project, it would be best to discuss with your roofer which material would be right for your roof.
Another factor you will need to consider is sarking, which is a waterproof layer of aluminium foil on a paper or plastic backing, installed beneath the battens of a metal or tile roof. This reflective surface is used to keep out moisture, reflect heat and prevent condensation forming under the roof.
Reflective sarking is one of the cheapest insulation options available, starting at around $100 for a 60m x 1.35m roll. Extra-heavy-duty sarking, for use under terracotta and concrete-tiled roofs, will set you back around $150 for a 30m x 1.5m roll. Reflective foil insulation designed to meet BCA 6 Star energy efficiency regulations will cost extra.
The roof plays a critical role in determining the temperature inside your home. While your roof’s ability to trap heat can be great during the chill of winter, it can turn your house into a sauna during the hot summer months.
This is where ventilation comes in. Correctly placed openings in the roof space allow airflow through the area, and are covered with wire or mesh to keep out pests and dirt. A more expensive option is to install controllable vents, which allow you to direct heated air through your house when you want it, or expel it as quickly as possible.
Who can install my new roof?
It’s recommended that you enlist the services of a roofer as early as possible so they can provide input on materials and costs right from the start. Most Australian states require roofers to be licensed, and you can search online for a suitable company in your area.
Before you hire a roofer, ask them the following:
- Are you properly licensed?
- How long have you been in business?
- Do you have the necessary insurance to work in my home?
- Can you provide me with a written cost estimate?
- What’s included in this quote?
- Do you have references and past jobs I can inspect?
- Is there a warranty on the materials you use?
The answers each contractor provides, along with any recommendations from family and friends, will help you make your final decision.
Other roofing tips
Keep these tips in mind when choosing and maintaining your roof:
- Regular maintenance.
- Many Australians tend to forget all about their roof until something goes wrong, such as a leak or a loose tile. Inspecting the area a few times a year and performing any necessary maintenance tasks will prevent minor issues turning into expensive problems.
- Do your research.
- A roof is a huge investment not only in terms of cost, but also in terms of how long it will last. Make sure you do plenty of research and are happy with your choices before you lay out any money.
- Check with council.
- Before you make any payments, find out from your local council whether there are any restrictions on the roofing materials or colours you can use.
- Remember that there are several factors that can affect the cost of your roofing project, including the material you select, the size of the job and the pitch you are planning. With this in mind, compare quotes for a number of options before you make a final decision.
- Roof repairs.
- Never put off a repair job on your roof, as this only increases the potential for more costly damage to occur. The work required to repair a metal roof will be much greater than repairing a tiled roof, so make sure you choose a roofer or tiler with the right experience for the job. Metal roof repairs start at around $40 per square metre.
- Roof restoration.
- If your roof is particularly old or damaged, you may opt to restore it completely. This can involve making sure it is waterproof, removing dirt and mould, replacing broken tiles and re-painting, to bring it back to its original condition. Restoration costs can range anywhere from $2,500 to $15,000, depending on the state the roof is in and the size of the area that needs to be repaired.