What Is Roof Sarking? Is Sarking the Same as Insulation? Is Roof Sarking Necessary?

Australia’s weather can be unpredictable, ranging from scorching sun to heavy rainstorms. Our homes serve as a refuge from these elements, requiring resilient roofs to ensure safety and comfort.

A practical solution for weather protection is roof sarking, offering effective security for you and your family. When combined with roof ventilation and leak prevention measures, roof sarking becomes a reliable method to safeguard your roof and enhance overall home security.

But first, we’ll get to know what is roof sarking:

What Is Roof Sarking?

Roof sarking is a material that is installed under the roof covering (such as tiles or metal sheets) during the construction or renovation of a building. It is typically a thin, flexible sheet made from various materials, including foil, reflective foil laminate, or synthetic materials like polyethylene.

The primary purpose of roof sarking is to provide additional protection and insulation for the building. Some of its key functions include:

1. Waterproofing: Roof sarking acts as a secondary barrier against water infiltration. It helps prevent water from entering the roof space during heavy rain or storms, protecting the structure and insulation from water damage.
2. Thermal Insulation: Roof sarking can contribute to the thermal performance of a building by providing an additional layer of insulation. It helps in reducing heat transfer between the external environment and the interior of the building, making it more energy-efficient.
3. Condensation Control: By acting as a vapour barrier, roof sarking helps control condensation within the roof space. This is particularly important in regions with varying temperatures, as condensation can lead to issues such as mould growth and degradation of insulation materials.
4. Dust and Pest Barrier: Roof sarking can act as a barrier against dust, dirt, and pests, helping to maintain a cleaner and healthier roof space.
5. Reflective Properties: Some types of roof sarking have reflective surfaces that can bounce back a portion of the sun’s radiant heat, potentially reducing the heat absorbed by the roof and improving the building’s overall energy efficiency.

The specific type of roof sarking used may vary based on factors such as climate, building design, and local building codes. It is typically installed during the construction process, positioned between the roof framing and the outer roof covering.

Is Sarking the Same as Insulation?

Roof sarking and insulation serve related but distinct purposes in the construction and thermal management of a building. While both contribute to the overall energy efficiency and comfort of a structure, they have different functions and are often used together for optimal results.

1. Roof Sarking:
   • Function: Roof sarking primarily serves as a protective layer against water penetration, dust, and pests. It acts as a secondary barrier between the outer roof covering (such as tiles or metal sheets) and the underlying structure.
   • Materials: Roof sarking can be made from materials like foil, reflective foil laminate, or synthetic materials. Some types may have reflective surfaces to provide additional benefits in terms of heat reflection.
   • Installation: It is typically installed on the exterior side of the roof framing, beneath the outer roof covering.
2. Insulation:
   • Function: Insulation is designed to resist the transfer of heat, helping to maintain a comfortable temperature inside the building. It reduces heat flow through walls, ceilings, and floors, thereby improving energy efficiency.
   • Materials: Insulation materials vary and can include fibreglass, foam boards, mineral wool, or other materials with high thermal resistance. The choice of insulation material depends on factors such as local climate, budget, and specific thermal performance requirements.
   • Installation: Insulation is installed within the building envelope—between walls, in the attic, or under the floor—to slow down the transfer of heat.

In many cases, roof sarking and insulation are used together in building construction. The roof sarking provides a protective layer, while insulation materials are installed to reduce heat transfer and improve energy efficiency. The combination of both can enhance the overall thermal performance of a building, providing benefits such as temperature control, energy savings, and protection against external elements.

Is Roof Sarking Necessary?

The necessity of roof sarking depends on various factors, including local building codes, climate conditions, and specific construction requirements. While it may not be mandatory in every situation, roof sarking can offer several benefits and is commonly used for the following reasons:

1. Water Protection: Roof sarking acts as a secondary barrier against water penetration. It helps prevent water from entering the roof space during heavy rain, storms, or in the case of a damaged roof covering. This protection is crucial for preventing water damage, mould growth, and structural deterioration.
2. Condensation Control: By serving as a vapour barrier, roof sarking helps control condensation within the roof space. This is particularly important in areas with fluctuating temperatures, as condensation can lead to issues such as mould growth and insulation degradation.
3. Dust and Pest Prevention: Roof sarking serves as a barrier against dust, dirt, and pests, contributing to a cleaner and healthier roof space.
4. Thermal Insulation: Some types of roof sarking provide an additional layer of thermal insulation. While not a substitute for dedicated insulation materials, it can contribute to overall energy efficiency by reducing heat transfer.
5. Reflective Properties: Certain types of roof sarking have reflective surfaces that can reflect a portion of the sun’s radiant heat. This reflective property can contribute to keeping the building cooler in hot climates.

However, in some regions or specific building designs, local building codes and regulations may not require the installation of roof sarking. It’s important to consult with local authorities, architects, or building professionals to determine the specific requirements for your location.

Can you incorporate sarking into an existing roof?

Typically, roof sarking is included during construction since the membranes need to be placed directly beneath the roofing material. However, it is feasible to add sarking during a home renovation or when extending a home. If your roof is being re-tiled or replaced, you can integrate sarking before the installation is finished.

Roof Sarking Installation: DIY vs Professional

The installation of roof sarking is crucial for ensuring your home’s safety and comfort. Therefore, the installation process must be effective, a key consideration for your project. If you have the expertise and confidence, there are ways to install sarking yourself, particularly with the right tools.

DIY Installation:

While professionals possess the skills, tools, and expertise, if you prefer to install sarking yourself, consider the following factors:

1. Required Skills: To start sarking a roof, you need to consider the skills and tools necessary for the job. As the job involves working on a roof, being comfortable and confident with heights is essential. Having a ladder is necessary, and having an assistant to hold and watch it is crucial.

2. Precise Measurements: Your roof dimensions must be measured precisely, as incorrect sizes or measurements can lead to issues during and after the sarking installation.

3. Tools Required: The tools you use need to be of high quality, and they can be a bit pricey. To install the sarking sheets underneath the roof tiles, you’ll have to remove the ridge capping, unfasten the clips, and dismantle the roof battens. For the most effective and efficient job, having the best tools is essential. Consider safety precautions such as wearing protective clothing, eyewear, and comfortable shoes that allow easy movement.

Impact of Incorrect Sarking:

If issues arise during the sarking installation, problems like leaks and roof damage can occur. Storm-driven rain entering your roof space, without proper sarking directing it towards the gutter, can lead to water damage. Incorrect installation can also result in air gaps, thermal bridging, issues with vapour barriers, and ventilation problems.

Hiring a Professional:

Roof sarking is a crucial process that requires extreme care for the best results. For the safest and most effective sarking, it’s advisable to hire a professional with the necessary skills and experience. Consider the following advantages:

1. Expertise and Experience: Professionals possess the expertise and experience to install sarking on both metal and tiled roofs. This is a complex process that demands a high level of skill.

2. Cost Considerations: The average cost of roof sarking in Australia varies based on thermal efficiency. While the cheaper option might be around $100 for a 60m x 1350ml roll, the more expensive option can cost around $350 for a 22.5m x 1350ml roll. Additional costs may apply depending on the contractor.

Investing in the expertise of a professional is worthwhile for peace of mind, especially considering Australia’s climate. Professionals ensure that your roof sarking protects your home, providing confidence against elements like bushfire embers.