What Is Roof Sarking, and Do You Need It?

Roof sarking to reflect heat

Wondering what is roof sarking?  Find out everything you need to know in our guide to roof sarking below, including whether you need it for your home, when is the ideal time to install sarking and what the best roofing insulation products are. For project specific advice, don’t hesitate to get in touch with the insulation specialists at Pricewise Insulation.

What Is Roof Sarking?

Roof sarking is a strong and pliable membrane which is installed under tiled and metal roofs. It essentially acts like a second skin, protecting the home from dust, moisture and draughts. Roof sarking is typically made with a reflective foil layer on one or both sides. This layer helps reflect the sun’s radiant heat away from your home, improving the overall insulation of your home.

What Are the Benefits of Sarking?

There are many benefits to installing sarking under roof tiles or a metal roof.

  • Moisture control – All sarking reduces the risk of mould growing in your roof cavity. Many sarking products also act as a vapour barrier, reducing and effectively managing condensation and preventing water damage.
  • Wind and dust barrier – Acting like a protective second skin, sarking reduces the amount of dust and wind draughts that can enter the roof cavity.
  • Increased thermal performance – Reflective sarking shields the house from radiant heat from the sun, improving comfort and energy efficiency.
  • Protection during construction – Roof sarking is installed before the roof is installed, which means it protects the exposed frame of your house from dust, wind and rain during the construction phase.
  • Fire protection – Sarking provides protection from embers during a bushfire and is mandatory in all homes located in bushfire prone areas from BAL12.5 to 40.

Is Sarking the Same as Insulation?

Sarking is classified as a type of insulation and will help increase the total R-Value of your home when installed properly. R-Value refers to how well the insulation resists the flow of heat. The higher the total R-Value, the better insulated your home is. Sarking alone does not usually provide enough thermal performance for your roof space. In most cases, bulk insulation products such as glasswool batts or polyester batts are installed between the ceiling rafters as well.

Does Sarking Reduce Heat?

Radiant heat from the sun can warm up a house very quickly. The reflective layer on sarking is designed to be a shield from radiant heat, reflecting it away from the home. This can help reduce temperatures inside your roof cavity, and prevent heat from transferring to the rest of your home. Installing reflective sarking as well as effective bulk thermal insulation can help improve indoor comfort. This means you’ll need to rely less on your air conditioner and heater to regulate temperatures, reducing your energy costs.

Does Roof Sarking Insulation Have an R-value?

The thermal performance of sarking products varies, depending on the specific application, orientation and installation method. Fletcher insulation offers a R-Value calculation tool which you can use to estimate the R-Value you can achieve using their Sisalation roof sarking products.

Is Roof Sarking Necessary?

If you are building a new home or renovating a metal or tiled roof, roof sarking may be mandatory depending on factors outlined in the Building Code of Australia. These include:

  • Whether you live in a bushfire prone area
  • Wind speed
  • Terrain category
  • Roof pitch

Can You Put Sarking in an Existing Roof?

It may be possible to install sarking in an existing roof if you are doing major renovations or home extensions. For example, if a tile roof is being re-tiled, it may be possible to install sarking before the new tiles are installed. The best time to install sarking is during the construction phase as the flexible membrane needs to be installed directly below the roofing material. The builder will roll out the sarking in sections, either in the same direction as the eaves or at right angles to them. The edges of the sarking sheets should overlap to ensure a complete seal.  The government’s Your Home website outlines the optimal installation methods for different roof types.

Can You Repair Roof Sarking?

Damaged sarking can usually be repaired using special tapes. It’s important to fix holes or tears in the material as sarking that has been damaged or torn may not do its job properly. Holes in the sarking can allow dust, moisture and draughts in and reduce the thermal performance.

How Much Does Roof Sarking Cost?

The cost depends on the type of roof sarking you buy, how heavy duty it is and what the thermal rating is. Costs typically range from $2 to $3 per square metre (p/m2). A 60 x 1.35 metre roll will typically cost between $180 to $300.

What Is the Best Roof Sarking in Australia?

At Pricewise Insulation, we supply Sisalation roof sarking products by Fletcher Insulation. Fletcher Insulation is an Australian manufacturer, offering a number of well known and respected brands that are used in homes across the country, including Pink Batts and Sisalation.

This is a double sided reflective sarking which can help reduce temperatures inside the ceiling space by reflecting 95% of radiant heat. It is made from an aluminium foil layer bonded to a tough kraft paper layer which is reinforced with strands of yarn.

This sarking is designed for use under concrete and terracotta roof tiles. It is made from a reflective foil layer bonded to a dense kraft paper layer which is reinforced with a coated polymer fabric. Sisalation Tile Roof Sarking will improve comfort and energy efficiency in the home and provide protection from weather if any tiles are broken or dislodged. Don’t forget to also insulate your roof space with bulk insulation! Check out our guide to the best roof insulation for more information.

Buy Roof Sarking Insulation Online Today

Check out the range of roof sarking and thermal insulation products we supply at Pricewise Insulation.  If you’re not sure which products are right for your project or have further questions after reading this article on “What is Roof Sarking?”, get in touch with our friendly team and we can help.

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9 thoughts on “What Is Roof Sarking, and Do You Need It?

    • Pricewise Insulation says:

      Hi Natalja,

      Thanks for commenting! We have a number of companies that we recommend, depending on the location and nature of the job. Feel free to call us on 1300 729 639 if you need a local installer, and we’d be happy to provide you with our recommendations.

      Kinds regards,

  1. SyllableCounter says:

    Great article! I never knew that roof sarking was such an important part of insulating a home. Thanks for the informative read!

  2. Helen Pitari says:

    I know it is best to install at construction but unfortunately it wasn’t in this case…so can we still install now, under maybe by nailing to ceiling somehow as we have a very high space in ceiling that we use as storage and we get a lot of dust & heat… is there some sort of solution you can think of please 🙏

    • Pricewise Insulation says:

      Hi Helen,

      Thank you for reaching out with your question!

      In your situation, retrofitting the Kingspan Aircell or Ametalin ThermalBrane range to the underside of the rafters is a viable solution. This not only enhances the thermal performance of your space but also effectively minimises the influx of dust into the roof area.

      If you have any more questions or need further guidance, feel free to ask. We’re here to help!

      Best regards,

  3. John McEwan says:

    We have recently had an electrician run some wires in our roof. The ran the the full length of the house on the side that has a 27 degree slope. This is the only side that has sarking. To avoid getting in the roof cavity the punched large holes in many location through our sarking. Since then our roof leaks everytime it rains. The water is only coming through on the side with the sarking. I am almost certain the damaged sarking is to blame because it was ok before their visit. I would greatly appreciate you professional opinion

    • Pricewise Insulation says:

      Hi John,

      Thank you for your comment!

      Based on the information provided, it seems like the roof sarking, which is primarily designed for reflecting radiant heat rather than acting as a water barrier, may have been compromised during the electricians’ work. While it might have offered some protection against rain before the damage, its primary function is not to prevent water ingress.

      In this case, the leaking issue could be related to the roofing material, such as tiles or metal sheeting. I’d recommend reaching out to a roofing professional who can assess the specific condition of your roof and identify any potential damages. They will be able to provide a more accurate diagnosis and suggest appropriate solutions to address the leaking problem.

      We hope this helps! Please feel free to reach out if you have any further questions.

      Warm regards

  4. joe says:

    hi i have old 1960s house with no sarking under terracotta tiled roof? I plant to try and retrofit sarking and wanted to know can it be stapled to the rafters?
    Also is sarking same as radiant barrier

    • Pricewise Insulation says:

      Hi Joe,

      Thanks for your comment!

      Regarding your question about stapling sarking to the rafters, it is indeed possible to retrofit a product such as Kingspan Air-Cell Insuliner between the rafters. This solution provides effective insulation while preserving the integrity of your roof structure. For more information on this product, you can visit the following link: Kingspan Air-Cell Insuliner Insulation

      In response to your query about the similarity between sarking and a radiant barrier, reflective sarking products like Kingspan Air-Cell serve as radiant barriers by reflecting the heat of the sun away from your home. This not only helps to regulate indoor temperatures but also contributes to energy efficiency and comfort.

      To delve deeper into how reflective foil insulation functions and its benefits, we recommend reading our informative blog post ‘How Does Reflective Foil Insulation Work?’

      We hope this information addresses your concerns. If you have any further question, please feel free to reach out to us on 1300 729 639. We’re happy to help!


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