In Australia, we have strict rules for fire safety, and choosing between 13mm and 16mm fire-rated sheets is one of the most common decisions you’ll face. Whether you’re fixing up a garage, adding a room, or working on a commercial shed, getting the thickness right matters for safety, your budget, and passing your building inspections.
What exactly is fire-rated plasterboard?
Fire-rated plasterboard is a heavy-duty wall and ceiling lining designed to hold back fire and heat for a set amount of time. While it looks a bit like the standard 10mm plasterboard you see in most houses, it’s built much tougher. Inside the core, there are special glass fibres and additives that stop the board from crumbling when it gets hot.
Think of it like a shield. Standard plasterboard is fine for a normal bedroom wall, but in areas where a fire is more likely to start (like a garage) or where you need to protect a neighbour’s property (like a wall on a boundary), you need that extra protection. In Australia, these boards are tested to make sure they can stand up to the heat without failing, giving you more time to get out safely.
13mm vs 16mm: What is the main difference?
The main difference between 13mm and 16mm fire-rated sheets is how long they can stop a fire and how heavy they are to work with. Essentially, the 16mm sheet is thicker and denser, which means it provides a higher level of fire protection compared to the 13mm sheet.
Because the 16mm board is thicker, it has more “fire-fighting” material inside. It stays solid for longer under extreme heat. However, that extra thickness comes with a lot of extra weight. A 16mm sheet is much heavier than a 13mm sheet, which means it’s harder to lift into place and usually requires more people or a specialized lifter to install. The 13mm is often seen as the “standard” fire-rated option for homes, while 16mm is the “heavy-duty” choice.
When should you choose 13mm fire-rated sheets?
You should choose 13mm fire-rated sheets for most residential jobs where the building code requires a basic level of fire protection. For “everyday Aussies” doing a home renovation, this is usually the go-to choice. It’s commonly used in the wall between your house and your garage or on walls that sit close to a fence or a neighbour’s house.
The great thing about 13mm sheets is that they are a bit easier on your back and your wallet than the 16mm version. They provide a solid level of safety that meets the requirements for most Aussie homes. If your builder or certifier says you need a “one-hour fire rating,” they are often talking about using 13mm sheets (sometimes in a double layer) to get the job done.
Recommended product: Siniat 13mm Fireshield Plasterboard
When is 16mm fire-rated plasterboard necessary?
16mm fire-rated plasterboard is necessary for high-risk areas like apartment buildings, commercial offices, and shared walls between different properties. If you are working on a set of units, a multi-storey building, or a shop, you will almost certainly be reaching for the 16mm sheets.
Because 16mm sheets are so thick, they are also fantastic at blocking out noise. If you have a wall that shares a boundary with a noisy neighbour or a loud street, 16mm fire-rated board is a brilliant choice because it’s so dense. It’s also used in places like lift shafts or stairwells in big buildings where people need as much time as possible to get out if a fire starts. It’s the “gold standard” for keeping heat and flames at bay.
Recommended product: Siniat 16mm Fireshield Plasterboard
How do fire ratings (FRL) work in Australia?
In Australia, fire ratings are measured by an FRL (Fire Resistance Level), which tells you exactly how many minutes a wall can hold up against a fire. You might see three numbers, like 60/60/60, on your building plans. This isn’t just random code; it’s a timer.
The first number is about how long the wall can hold weight without collapsing.
The second number is about how long the wall can stop smoke and flames from leaking through cracks.
The third number is about how long the wall can keep the other side cool so things don’t catch fire just from the heat.
Choosing 13mm or 16mm depends on which rating your specific project needs to hit. The 16mm board will always give you a higher “minutes” count than the 13mm board when used the same way.
Can I just use 13mm instead of 16mm if it’s cheaper?
No, you cannot swap 16mm for 13mm unless your building certifier says it is okay in writing. Fire safety rules are there for a reason, and if your plans say you need 16mm, that is exactly what you must use. If you try to save a few bucks by using thinner boards, you likely won’t get your final building certificate.
Even worse, if there ever was a fire and the wrong material was used, your insurance company might refuse to pay out. It is always best to stick to what is on the plans. If you aren’t sure, have a quick chat with your builder or a professional supplier to make sure you’re buying the right stuff for the job.
Helpful tips for installing fire-rated sheets
Fire-rated sheets are heavy and require special screws and sealants to work properly, so don’t treat them like standard plasterboard. Because they are so dense, you need to use specific “fine thread” screws that can bite into the core of the board. Normal screws might just spin or fail to hold the weight over time.
Also, remember that a fire-rated wall is like a chain—it’s only as strong as its weakest link. If you have gaps around power points or where the sheets meet the floor, the fire will get through. You need to use “fire mastic” or fire-rated sealant to plug every single gap. And since 16mm sheets are particularly heavy, don’t try to be a hero and lift them alone. Use a plasterboard jack or get a couple of mates to help you out.
Get the Right Gear for Your Project
At Building Supplies Australia Network, we make it easy to get exactly what you need. We deliver quality building supplies right across Adelaide, Brisbane, Melbourne, and Sydney. Why spend your weekend driving back and forth to the shops? Order online today or request a quote to get your fire-rated sheets delivered straight to your site.