Underfloor insulation provides an effective barrier to the flow of heat through suspended timber sub-floors and helps reduce the reliance on heaters in winter and air conditioners in summer.

Once it’s installed, underfloor insulation tends to be forgotten. But if you’re an architect or tradie looking to recommend a relatively inexpensive upgrade that is easy and quick to install and adds long-term value for your client, then underfloor insulation should be near the top of your list.

Underfloor insulation, when installed correctly and when quality underfloor insulation products with high R-values are used, makes a noticeable difference. Your clients will notice a return on their investment in underfloor insulation and enjoy a home that is naturally more comfortable year-round with less heat loss in winter, and less heat gain in summer.

“If you’re an architect or tradie looking to recommend a relatively inexpensive upgrade that adds long-term value for your client, underfloor insulation should be near the top of your list.”

Underfloor insulation can also provide acoustic advantages in a home by dampening the sound of footsteps on timber floors. Along with wall and roof insulation, underfloor insulation also helps reduce the transfer of noises from outside to inside and vice versa.

What types of underfloor insulation are available?

 There are four main types of underfloor insulation products. Each one uses different kinds of materials and slightly different methods of installation.

Foilboard insulation

A rigid insulation panel featuring a fire retardant expanded polystyrene core covered with an aluminium layer of foil on both sides. With a fire retardant expanded polystyrene core, Foilboard provides a thermal break and vapour barrier for thermal performance and moisture resistance.

Glasswool underfloor insulation batts

Glasswool batts contain millions and millions of tiny air pockets to effectively slow down the flow of heat. Made from recycled glass materials and a cost-effective choice, Glasswool insulation products are pre-cut to fit between the joists of timber floors and can be strapped or stapled in place.

Polyester rolls

Polyester rolls are a type of bulk insulation that traps billions of little air pockets within their structure to slow down and break up the heat path. Made from recycled plastic materials and typically pre-cut to fit new and existing timber joist floors, polyester rolls are available in a range of thicknesses and R-values.

Rigid expanded polystyrene (EPS) panels

One of the most popular choices for underfloor insulation, expanded polystyrene foam panels are a cost-effective and energy-efficient underfloor insulation to effectively make any home with a timber floor more comfortable all year round.

Rigid EPS panels like Expol Underfloor Insulation are designed to be easy to install, making them perfect for tradies looking for a product to recommend or architects to specify when designing a new home for clients.

How underfloor insulation adds value

Installing underfloor insulation can add long-term value to that new home you are designing or the existing home you are working, by making it a more cost-effective, efficient, and comfortable place to live.

Underfloor insulation can occasionally be overlooked by architects, builders, and tradies, but it can delight your customers, who will gain a naturally more comfortable home. Here are five ways quality underfloor insulation will enhance any home with a suspended floor.

Reduce drafts

By creating a barrier that wind cannot pass through, underfloor insulation helps eliminate drafts in homes that are raised above the ground.

Prevent heat loss

Insulation reduces temperature change, meaning less energy is needed to maintain the preferred temperature inside a home.

Reduce unwanted moisture

Timber floors are particularly vulnerable to moisture. Installing underfloor insulation creates a ‘vapour barrier’ that prevents moisture from gathering on the underside of a raised wooden floor, which over time may cause the floor to warp or become stained.

Pipe protection

For those living in the colder parts of Australia in homes with piping beneath their timber floor, underfloor insulation provides an additional level of protection when the water in the pipes reaches freezing temperature. This can cause the pipes to crack or even burst.

Make summers manageable

Not just for winter, underfloor insulation also helps to control the temperature inside a home during the warmer months, relying less on air-conditioning.

Underfloor insulation for tradies

Underfloor insulation is lightweight, making it quick and easy for tradies to transport, work with, and install. Expanded polystyrene foam panels like Expol are readily available through retailers and offer a truly hassle-free installation. When working with Expol Underfloor Insulation, the basic installing steps include:

  • Measuring the distance between your joists and purchasing either the 560mm, 470mm, 410mm, or 360mm width.
  • Cutting the panel to size if needed, including leaving room for things like pipes, plumbing, or cables.
  • Sliding the panel between the joists and pushing it so it is pressed against the floorboards to ensure there are no air gaps.
  • Fixing supplied fittings in place at the panel’s corners.


“Underfloor insulation is lightweight, making it quick and easy for tradies to transport, work with, and install.”

While some underfloor insulation products can be tricky and time-consuming to install, Expol Underfloor Insulation is quick and easy to install, making these rigid panels the material of choice for tradies, and also for architects specifying the best products to use on their projects.

Trusted for more than 20 years, Expol Underfloor Insulation is available in four convenient joist widths (560mm, 470mm, 410mm, 360mm), and can easily be self-installed by competent DIY’ers and tradies alike.