How Much Does Roof Insulation Cost to Install in Australia?

Looking to insulate your roof and wondering how much it will set you back? Check out our guide to roof insulation costs below or get in touch with our team of experts for more tailored advice.

What Does Roof Insulation Cost?

HireTrades estimated that the average cost of insulating a 100 square metre roof is between $1,100 and $5,200. The truth is, the final cost will depend on a number of factors, including:

Climate and R-value

The R-Value of an insulation product indicates how effective it is at preventing heat loss and gain. Products with a higher R-Value will be more expensive than lower R-Value options. For example, you can expect to pay around $9 per square metre for R3.5 Knauf Earthwool ceiling batts compared to over $18 per square metre for R6.0 Earthwool ceiling batts. The table below shows the total estimated cost of insulation for a 100 square metre roof with Knauf Earthwool using different R-Values, and assuming a DIY installation.

Depending on the climate where you live, you may need an even higher R-Value to help regulate temperatures effectively. If you are renovating, you may also be required to meet certain R-Value standards according to local building regulations.

Size and Type of Roof

The larger the area you need to insulate, the more square metres of insulation you will need and the higher the installation costs will be. Accessibility to the roof space may also affect the installation costs. It is often possible to install roof insulation from the inside, whereas roofs with no crawl space may require some of the roofing material to be temporarily removed. The type of roof you have may also affect the method and products used in the installation. If you're not sure what's best for your project, a professional can guide you through the right insulation for your roof.

Purpose and Goals

What you plan on using your roof space for may affect how you insulate it and therefore the final cost. For example, if you are simply topping up the existing insulation in your roof with new insulation, it might be cheaper than if you plan on using the roof space for storage or converting the attic into a liveable space. Attic conversions will require insulation between the ceiling joists (which serve as floor joists in the attic) as well as attic insulation between the roof rafters to ensure the area is habitable and compliant with building regulations. You may also want to invest in acoustic insulation to stop noise being transferred to the rooms below the attic. Read also: How to work out the cost of adding insulation to your attic.

Types of Roof Insulation

Some of the best roof insulation products in Australia include:

Reflective Foil Insulation

Reflective insulation products help reflect radiant heat from the sun away from your home, which can help prevent the roof space from overheating. Two of our most popular reflective insulation products are:

• Kingspan Air-Cell Insulbreak 70 – costs around $395 for 30 metres
• Kingspan Air-Cell Insulwhite® Insulation – costs around $510 for 30 metres

Roof Sarking

Most homes have a layer of roof sarking under the roofing material which acts like a second skin to the home and improves the overall R-Value. Heavy duty sarking for metal roofs such as Trade Select by Ametalin will set you back about $80 per 45m2 roll.

Glasswool Batts

Glasswool insulation is one of the most popular insulation materials because it is affordable and highly effective at resisting heat transfer. Glasswool batts are a type of bulk insulation - they contain millions of tiny air pockets in their structure which break up the pathway of heat to slow down heat transfer. Some of our most popular glasswool products for roof applications include:

• Knauf Earthwool ceiling insulation batts
• Fletcher Pink Batts glasswool ceiling insulation
• Bradford Hi-Performance Gold ceiling batts

Polyester Batts

Polyester insulation is a more premium bulk insulation product than glasswool. As it is made from 100% polyester and contains no breathable fibres, it is particularly suitable for people with dust allergies. R4.0 polyester batts cost around $39 per square metre. One of our most popular polyester products is:

• Bradford Polymax Thermal Ceiling Insulation Batts

Blanket Insulation

Blanket insulation is available in rolls of a single length, whereas insulation batts come pre-cut into shorter pieces. Some blanket roofing products come with a reflective foil layer to help reflect radiant heat. Popular blanket insulation products include:

• Knauf Earthwool Roofing Blanket with Foil Facing
• Fletcher Permastop Building Blanket

Loose Fill Insulation

At Pricewise Insulation, we don't recommend using loose fill insulation or spray foam insulation as it has a number of disadvantages compared to insulation types like batts and blankets. Read more Expanding foam vs insulation batts - which is better?

Can You DIY Roof Insulation?

Some people decide to install roof insulation themselves in order to save on installation costs. If you have safe access to your roof space and know how to safely and correctly install the insulation, it's possible to do it yourself. If you're considering a DIY installation, be sure to check out our DIY insulation videos before you get started. Installing insulation in the roof can be a hot and dusty job and care should be taken to avoid any health and safety hazards. Keep in mind that insulation batts must not be compressed or have any gaps left between them when they're installed. Hiring a professional can give you peace of mind that the job will be done to a high standard. Professional insulation installers can also help you get the best products for your application. Get a fast and accurate quote for roof insulation installation in Melbourne or Sydney from Pricewise Insulation today.

Ready to Get Started? Order Your Insulation Online Today.

Whether you decide to do it yourself or hire a professional, installing insulation in your roof is a smart move that will benefit your home for years to come. Not only does roof insulation help keep temperatures inside comfortable all year round, it'll also improve the energy efficiency of your home and lower your energy bills. Ready to get started? Head to our online store to place an order for the products you need. Or give us a call on 1300 729 639 to discuss your project.