Won't sag. Won't settle. Won't quit.
Rigid-board underfloor insulation you install yourself. No tradies. No quotes. No install fees. Backed by a 50-year warranty.
Bunnings
Mitre 10
Home Timber & Hardware
Dahlsens
Bowens
Independent Hardware Stores
50 yr
Up to20 %
1984
0%
Rigid-Board Underfloor Insulation
Won't sag.
Won't settle.
Won't quit.
Rigid-board underfloor insulation you install yourself. No tradies. No quotes. No install fees. Backed by a 50-year warranty.
Do it once. Do it right.
Two floors.
Two methods.
Whether you’re retrofitting under an existing home or insulating before the floor goes down on a new build, the Expol system has the right panel and the right accessory to hold it in place. Tool- free either way.
Retrofit from below.
Crawl under the house. Push-fit Z Clips between the joists. Slide Expol panels up behind them. No tools, no nails, no drilling — and no need to lift the floor.
Install before the floor.
For new builds on timber or steel joists. Sit Joist Saddles on top of the joists, drop panels in from above, lay your floor over the top. Faster than batts, and it stays put for the life of the build.
Two boards.
One decision. Easy.
Same rigid EPS core. Same 50-year product warranty. The only real question is which one suits your home.
1.4
Expol White
The one most Australian homes need. Reliable rigid-board thermal performance at a price point that makes insulating the whole house an easy yes.
1.8
Expol Black
Graphite absorbs radiant heat, giving Black 30% more thermal efficiency than White. For cooler climates, bigger houses, and homeowners who want their energy bill to feel it.
The bits that make it work. Quietly.
Other rigid boards rely on nails and hope. Expol’s accessories hold the panel in place – properly – whether you’re retrofitting from below or building from above.
Z Clips
Push-fit clips that wedge between joists to hold the panel from below. No nails. No drilling. No dropped panels three years later.
Joist Saddles
Saddle fits over the top of the joist before the floor goes down. Panels drop in behind it. Faster than nailing. Stays put for the life of the floor.
No installer.
No quote. No drama.
The reason Expol exists is that underfloor insulation doesn’t need a tradie. You can measure your own joists, drive to a hardware store, and fit the panels yourself in a weekend. Here’s how three steps actually look.
Measure up
01
Check the distance between your floor joists and the total area you want to insulate. Our calculator turns that into an exact pack count — no guessing, no over-ordering.
Pick it up
02
Head to one of our stockists or order online if you’re in VIC or SA. Panels are light — a full pack fits in the back of most utes and sedans.
Fit & forget
03
Z Clip or Joist Saddle, push the panel into place, move on. The concertina-cut edges compress up to 20mm for a snug fit — no cutting, no tools, no mess.
Up to 20% of your heat leaks through the floor.
20%
Of your home’s heat disappears through an uninsulated floor.
12%
Typical reduction in household energy use after retrofit.
$0
Installer fees, because you install it yourself.
50
Year product warranty — longer than your mortgage.
Under a floor, staying put is the whole job.
Underfloor is the one place insulation has gravity working against it around the clock. Whatever you install has to hold full contact with the floor above, not just on day one but for decades. Rigid EPS does that by nature. It holds its shape, so it holds its performance.
The Gravity Problem
Under a floor, soft insulation relies on straps, staples or tension to stay pressed against the floorboards. Any gap that opens between insulation and floor lets cold air in exactly where you don’t want it, and the rated R-value only applies while full contact holds. Installed well, soft systems can do the job. But under a house is not somewhere you want to go back to check.
0mm
Same shape in 50 years
Expol is closed-cell EPS, a structural foam that holds its dimensions for the life of the building. Concertina edges compress 20mm to lock between joists with friction alone, no fixings needed for a snug fit. It can’t sag because it’s rigid, so full contact with the floor is built in. The R1.4 you install is the R1.4 your floor still has decades later.
R1.4
Crawling under your house is not something you want to do twice. A rigid panel holds its shape, its position and its R-value, so the job you finish this weekend stays finished.
Batts sag. Rolls slump. Rigid stays put.
Soft insulation loses up to 40% of its performance over two decades — it compresses, slides, and in the worst cases becomes a warm home for rodents. Expol’s rigid EPS board holds its thickness, its R-value, and its position. For the life of your floor.
Sags. Sinks. Nests.
Soft batts and rolls compress under their own weight. Gaps open up between joists. Rodents move in. The R-value you paid for quietly disappears — and by the time you notice, it’s a floor-up job to fix it.
Stays. Seals. Lasts.
A rigid EPS panel, concertina-cut on both sides to compress up to 20mm for a snug fit between your joists. It doesn’t sag. It doesn’t slump. It doesn’t make a good rat nest. And it’s guaranteed for 50 years.
They did it once. They did it right.
- Verified install
“Expol Black transformed our new extension from icy cold to toasty warm. So easy I did it myself. Now I’ve got to do the whole house!”
Fleur R.
- Verified install
“Light, super easy to cut and fit perfectly in a small crawl space. Noticeable warmth on our timber floorboards and in our large room.”
Colin L.
- Verified install
“Pink batt insulation is messy and falling apart. Installed Expol over the pink batts. Easy to install, cut to size and so neat and tidy.”
Mak R.
- Verified install
“Expol insulation increases heat retention, reducing heat pump use and our power bills. Modifying the panels for size, cables and pipes is easy.”
Priya M.
- Verified install
“Fantastic product. We installed it at our new bush build where it snows, and at our daughter’s house. It made a huge difference overnight.”
Lisa J.
- Verified install
“After a great deal of research, this was the easiest way to insulate, as I have to crawl under the house. People have noticed the difference when they walk in the house.”
Dave R.
Verified installs
They did it once. They did it right.
In-store near you.
Online if you'd rather.
Expol is stocked across Australia through the big trade chains and quality independent merchants. Enter your postcode to see what’s nearby — or head straight to the online shop if you’re in VIC or SA.
Quick answers.
The questions we hear most often from people about to order — sorted in 30 seconds. For the full list, head to the FAQ page.
What is Expol underfloor insulation?
A rigid EPS board that sits between the joists under a suspended timber floor. Because it’s rigid it holds its shape and stays put, so it won’t sag or drop out the way batts and rolls do once they’ve copped a few winters. Less heat leaks through the floor, the floor’s warmer underfoot, and you fit it yourself.
What's the difference between Expol White R1.4 and Expol Black R1.8?
Expol White R1.4 is the standard underfloor insulation panel, while Expol Black R1.8 is the higher-performance graphite-enhanced option for suspended timber floors.
Expol White R1.4 is a reliable, cost-effective choice for improving comfort and reducing heat loss through timber floors. It is ideal for most underfloor insulation projects where homeowners want a proven Australian-made EPS insulation panel.
Expol Black R1.8 is designed for stronger thermal performance. It is made with graphite-enhanced EPS, which helps it achieve a higher R-value than Expol White R1.4. Expol Black R1.8 is around 30% more thermally efficient than Expol White R1.4, making it the better choice when maximum underfloor insulation performance is the priority.
Where can I buy it?
Through building and hardware merchants like Bunnings, Mitre 10, Home Timber & Hardware and Dahlsens. In Victoria and South Australia you can also order online from The Foam Shop and have it delivered.
How do I know which panel width to buy?
Measure the gap between your joists, inside edge to inside edge. Panels come in 410mm, 470mm and 560mm to suit common Australian joist spacings, so pick the width closest to your gap and trim if you need to. Joist spacing isn’t always consistent, so measure in a few spots first.
How much does a pack cover, and how many do I need?
A standard 410mm pack covers 5.41m². Coverage shifts a little with panel width, and you’re not insulating the whole floor footprint because the joists take up room. So the honest answer is to use the calculator: put in your floor area and joist spacing and it gives you an exact pack count, with a bit of allowance for trimming. Beats counting panels in your head.
Do I need any accessories, and what is WireGuard for?
Depends on the job. For a new floor, Joist Saddles hold the panels in place from above before the floorboards go down. For a retrofit, Z Clips push up between the joists from below, no nails or drilling. WireGuard is the one to watch: wherever a panel would sit against an electrical cable, it goes in between to keep the panel off the wiring. Before you start, have a look under the floor for cables, pipes and anything else in the way.