Roof Sarking & Insulation: Can You Have Both?

Roof sarking is a critical part of a properly installed roof system. It provides protection to your underlayment and insulation, so they last longer and perform better. Roof sarking also increases home energy efficiency because it protects the house’s structure from moisture and UV damage.

What is roof sarking used for?

Sarking is the quiet workhorse of your roof — a thin, flexible layer (usually foil or laminate) that sits just beneath your roofing material, right above the frame or insulation. It acts like a protective second skin, shielding your roof cavity from water, dust, radiant heat, and even ember attack during bushfire season.

Watch this video for a quick 101 on sarking:

Here’s what sarking actually does in plain terms:

• Redirects water if roof tiles crack or metal sheets shift
  
• Controls condensation that forms in the roof cavity
  
• Blocks dust and debris from settling in your insulation
  
• Reflects radiant heat to help your roof stay cooler in summer
  
• Improves thermal performance, especially in Perth’s intense heat
  
• Provides a vapour barrier that keeps moisture where it belongs
  

So, what is sarking used for? It’s used to reinforce your roof structure, increase durability, and improve overall performance — whether your home has roof tiles, metal sheets, or a combination of both.

Is Sarking Waterproof?

Sarking isn’t fully waterproof like your roofing material, but it’s highly water-resistant — and it’s designed to step in when your outer layer doesn’t hold up.

When installed correctly, sarking:

• Redirects water away from the roof cavity
  
• Minimises leaks caused by broken tiles or wind-lifted metal sheets
  
• Prevents moisture buildup that can damage insulation and framing
  
• Works in all roof types, especially in tile and metal roof systems common across Perth homes
  

In short: it won’t replace your roof tiles or Colorbond sheets, but it will catch leaks, reduce heat gain, and give your roof a longer, healthier life.

---

Can I Install Sarking On An Existing Roof?

Yes — sarking can be added to an existing roof. It’s best done during:

• A full or partial re-roof
  
• Storm damage repairs
  
• Renovations or home extensions
  
• Upgrades to insulation or energy efficiency
  

To retrofit it properly, your roofing material needs to be lifted or temporarily removed. That gives your roofer access to the battens and roof structure, where the sarking is rolled out and fastened using proper fasteners.

The end result? You get a modern, high-performance upgrade without changing your roof’s appearance — and without compromising ventilation or roof space airflow.

---

Why Sarking Matters in Perth

If you live in WA, you already know our heat, dust, and sudden rain events aren’t kind to roofing systems. That’s exactly why more homeowners are choosing to include sarking — especially on metal roofs, where condensation can quickly become a problem.

• Radiant heat: Perth sun beats down hard — sarking reflects much of that sun’s radiant heat before it enters your home
  
• Dust: Our dry conditions send fine red dust into every gap — sarking helps keep your roof cavity clean
  
• Moisture: From winter storms to humid mornings, sarking adds a vital barrier against water and dampness
  
• Roof space control: Helps keep your ceiling cavity stable, dry and breathable, improving overall performance year-round
  

And for bushfire zones, sarking offers added resistance against embers, helping meet compliance and giving extra peace of mind.

---

Works With All Roof Types

Whether you’re working with tiles, metal sheets, or a combination of roofing materials, sarking adapts:

• Under roof tiles, it sits neatly beneath the battens, forming a continuous layer
  
• In metal roofs, it’s key for managing condensation and reducing heat transfer
  
• On a new roof, it’s one of the first components installed for thermal performance and protection
  
• In renovations, it integrates with existing insulation for an instant upgrade
  

It’s flexible enough to suit different roof areas, pitches, and shapes — and smart enough to keep performing no matter what Perth weather throws at it.

What Does It Actually Look Like?

Most modern sarking comes as a foil-laminated roll — usually with reflective silver or shiny backing. Some are single-layer, others are multi-layered for extra strength and protection.

You’ll see terms like:

• Reflective foil insulation
  
• Sarking sheets
  
• Roof wrap
  
• Radiant barrier
  
• Vapour barrier membrane
  

They’re all part of the same family — and choosing the right one depends on your roof type, roof area, and your home’s exposure to heat, moisture, or dust.

---

Can You Have Roof Sarking and Insulation Together?

Yes — and in most cases, you should.

Sarking and insulation aren’t an either-or decision. When installed together, they form a double-act that dramatically improves your roof’s thermal performance and weather resistance.

Here’s how they work together:

• Sarking forms a protective layer just under the roof, deflecting radiant heat and moisture
  
• Insulation sits just beneath that — keeping internal temperatures stable and reducing heat transfer into the home
  
• The result: better energy efficiency in summer and winter, less moisture damage, and a cleaner roof space
  
• For homes with metal sheets, this combo helps prevent condensation from forming under the roof, protecting both materials and comfort
  

Whether you’re working with new roof builds, renovations, or upgrading an existing roof, installing sarking and insulation together makes a huge difference in overall performance — without sacrificing ventilation or breathability.

---

FAQs

Does sarking replace insulation?
No — it works with it. Sarking keeps insulation dry and clean, and improves heat deflection.

Can it block airflow?
Not when installed properly. Vents, breathable sarking types, and good design ensure airflow stays intact.

How long does it last?
Most sarking lasts 20–30 years, depending on quality and conditions.

Is sarking worth it for all homes?
Yes — especially in Perth’s heat and dust. It works with any roofing material, and suits both tiles and metal sheets.

---

Final Word

You don’t see sarking — but you’ll feel the difference.

It makes your roof smarter, stronger, and better equipped for WA’s extreme weather. Whether you’re building new, re-roofing, or just sick of your roof space dripping with condensation, sarking is a simple, powerful upgrade.

Want to find out if your home needs sarking?
Book an inspection and quote with Roof Repairs Perth WA — we’ll assess your roof structure, insulation, and ventilation, and recommend the best fit for your home.