Roofing is a complicated process that has a lot of parts, all of which need to work together to make a roof both durable and functional. Sarking is just one aspect of this, but it’s often overlooked by those who are not professional roofers. In short, sarking is a layer of material that rests beneath the tiles or sheets on metal roofs, serving as an extra protective barrier against the elements.
Roof sarking is a vital stage of the construction process because it affects the overall performance of the roof. Whether you are building a new house or considering a roof replacement on your existing home, you need to understand sarking to ensure your roof is fully functional. In fact, the Building Code of Australia (BCA) now requires sarking on new homes.
Let’s explore the ins and outs of sarking, why it’s important for your roof, and what types are available.
What is Roof Sarking?
Roof sarking is a thin layer of material that goes beneath the roof’s outer layer, whether that’s tiling or metal sheets. It is a thin, flexible membrane that provides extra structure to the roof, like a protective second skin. Sarking can be made from various materials, including foil, bitumen, or a breathable membrane made from synthetic fabrics. Typically, it is installed during the construction of a new roof, but homeowners can also retrofit it to an existing roof.
The main purpose of roof sarking is to provide a protective barrier, filling any gaps left by the outer layer. It keeps the roof cavity dry by preventing water from entering through the gaps, but it also acts as a form of roof insulation to reduce heat loss through the roof of the house.
As a result, roof sarking is particularly important in areas with adverse weather conditions, including heavy rainfall or even bushfire-prone areas.
What Are the Benefits of Roof Sarking?
It’s highly recommended to install sarking in your home due to its many benefits. Here are four of the significant advantages of installing sarking.
1. Protects Your Roof Cavity
Firstly, roof sarking protects the roof space by covering any gaps between the metal sheets or tiles. Not only does this prevent leaks from rain, but it also acts as a dust barrier to prevent debris from entering the roof cavity. The vapour barrier can protect your home from unseen mould growth, which poses a serious risk to your home.
It can also prevent wind from entering the roof space, which is ideal for protecting against potential damage and helps to ensure a comfortable living space for your family.
2. Improved Thermal Performance
Sarking insulation can also boost your house’s thermal performance by providing a layer that reflects the radiant heat coming through the roof. As a result, sarking insulation is ideal even in warmer climates because it can cool your space and improve energy efficiency.
The reflective foil layer can actually reflect up to 97% of the sun’s radiant heat, ensuring your house remains cool when it’s too hot outside.
At the same time, effective roof insulation also keeps your house warmer during the colder winter months. Having a more effective thermal performance makes your house more energy efficient, helping you to cut the costs of energy bills.
3. Fire Protection
Roof sarking is great for bushfire protection, too. The membrane is fire-proof, preventing bushfire embers from entering the roof space and stopping a potential fire from sparking in your home.
Many insulation materials are flammable, so if you live in a bushfire-prone area, make sure you get fire-resistant sarking.
4. Moisture Control
As well as stopping rain from entering the roof cavity, sarking can also reduce moisture build-up from other sources.
Let’s say you live in a cooler climate and have a metal roof. The warmer air inside your home can rise in the roof cavity, hitting the cold metal sheets and turning into condensation, which drips back down into the ceiling space. If there is too much moisture and condensation in the roof space, you may face costly repair problems down the line.
Roof sarking acts as an insulating barrier between the roof and the space, preventing this from happening.
What Are the Types of Roof Sarking?
Sarking can be used whether you have a metal or tiled roof, which are the two most common roofing types in Australia. The type of sarking you choose and how heavy duty it is will depend on the roof you have. It can also depend on where you live.
Tile roofs are best suited to a fine sarking membrane that sits between the rafters and battens. A breathable membrane allows for air exchange between the roof space and the outside, helping to prevent moisture buildup.
Typically, this membrane is made of synthetic materials like polyester or polypropylene, both of which are lightweight and durable. With professional installation, the sarking sheets are fitted with an overlap of at least 100mm, ensuring a watertight seal that accounts for any gaps in the tiling.
Even if your roof is well-installed, cracked tiles can lead to leaks. Getting the right sarking is the best way to prevent that.
Metal roof sarking comes in many forms. There are some stronger insulation options for colder climates, or thinner sheets that are more waterproofed to protect homes against rain.
Thermal insulation is also ideal if you live in a busy area, because it can also improve the acoustic performance of your roof. In other words, it can help to block out the external noise from a busy street or nearby airport.
Installing Roof Sarking in an Existing Roof
Generally, constructors install sarking during the roof installation itself. Roof sarking can protect the bare roofing materials during construction, which is an added benefit to installing it while building the house.
That said, it’s also possible to install roof sarking on an existing roof. Professional installation is recommended to ensure it is installed properly, but it’s also something you can do yourself.
Make sure you consider the following steps:
- Sag the sarking sheets to ensure proper insulation and drainage with the gutter.
- Create air gaps between the roof membrane and the underside of the roof sheet to develop a drying path.
- Tape down the vertical overlap amidst the roll joins to seal the sides and block any water from spilling into the roof cavity.
How Much Does Roof Sarking Cost?
The cost of roof sarking depends on various factors, including the type of material, its thermal rating, and the size of your house.
Generally, you can expect to pay $2 – $3 per square metre. A 60 x 1.35-metre roll costs somewhere between $180 and $300, but this doesn’t account for the labour costs of sarking installation, which can also vary depending on where you live and the size of your roof space.
Repairing Roof Sarking
Although roof sarking is generally quite durable, it can still tear or rip over time. You must repair roof sarking when this happens because any holes can prevent it from working properly. If you notice any leaks, water stains, or drafts in the attic, then it might be time to repair the sarking.
You might be able to repair minor damage using roofing tape, or a patch of the same material. However, if the damage is more extensive, you may need to replace the entire thing. Consult a professional roofer if you are unsure.
Wrapping up: Why Roof Sarking is Important
In summary, sarking is a protective layer for your roof, making it a vital component of your home’s construction. It can improve energy efficiency, reduce noise, and protect against the elements.
If you are building a new home or renovating the roof, make sure you research the best sarking for your needs and ensure it is installed properly.
Get in touch with us today to find out what the best roof sarking is for your home.
The top questions on roof sarking and its importance.
1. What’s the Difference Between Roof Sarking and Roof Insulation?
Roof sarking and roof insulation are both important components of a roof, but they serve different purposes. Roof insulation is solely there to reduce heat loss and improve energy efficiency, whereas sarking also keeps out water, wind, and fire embers. Both sarking and insulation can be used together to protect your roof effectively.
2. Do You Need Sarking under a Tiled Roof?
Yes, you should have sarking under both metal and tiled roofs. Sarking can cover any gaps left by the tiles, including broken tiles. If you want to make your roof durable, sarking is a must-have.
3. Is Sarking Mandatory in Australia?
Yes. The Building Code of Australia (BCA) requires sarking on all new roofs. For existing roofs, it’s recommended to retrofit sarking to improve your roof’s durability and your home’s energy efficiency. Your local council should be able to advise you on the best type of sarking for the local climate.
4. Do I Need Roof Sarking?
In general, sarking is beneficial for Australian homes due to the climate. On new homes, sarking is mandatory, but you should consider fitting it to existing roofs, too. It could be more important for you to install sarking depending on where you live, the local climate, and the material your roof is made of. However, in general, it’s recommended.