Underfloor Heating Underlay

To get the most value for money after the upfront cost of installing an underfloor heating system, you should install a suitable underfloor heating underlay.

Like all underlays, this will be fitted between the heating system and flooring surface, but it doesn’t just provide a stable finish over subfloor imperfections – the underfloor heating underlay is also essential for maintaining effective heating across different floor types.

Available in various thicknesses with low TOG ratings, these products are specifically designed to improve the efficiency of underfloor heating by enabling maximum heat transfer. They are typically made from robust materials like high-density rubber or flame-retardant foam to ensure practicality and safety.

While an insulating underlay will trap heat and reduce the efficiency of an underfloor heating system, a specialised underfloor heating underlay will reduce energy waste by preventing downward heat loss into cold areas, improving the response time of heating systems by enhancing heat transfer up to 20%.

Despite its low thermal resistance, the durability of UFH underlay means it can withstand continuous heat and maintain its structural integrity while providing cushioning for underfoot comfort and dampening impact noise from 15dB up to 46dB!

Being thinner and denser than other products designed for rooms without underfloor heating, such as thermal underlay, also makes our underfloor heating underlay suitable for areas with heavy foot traffic, including both domestic and commercial spaces.

Yes – underfloor heating typically works best with engineered wood flooring that can retain the warmth spread through the underlay. This is why our range at Simply Underlay includes several options for floating wooden floor installations at different price points.

Our premium bestseller is Duralay Heatflow Wood & Laminate Underlay, which has a 3mm thickness and a very low TOG rating of 0.35. Denser and slightly thicker at 3.6mm and 0.55 TOG, Duralay Timbermate Excel Underlay is also a bestselling product for wood and laminate floors.

For a more budget-friendly solution, you could choose Duralay Silentfloor Gold Underlay as your wood or laminate underlay for underfloor heating. This also has a very low TOG rating at 0.33, but offers a greater thickness at 4.2mm for enhanced comfort – though it isn’t compatible with electric/dry heating systems.

If you need advice on the best underlay for your specific type of wooden flooring and underfloor heating system, feel free to get in touch.

The best carpet underlay for underfloor heating that we stock at Simply Underlay is Wilsons ThermalStream Underlay. This 10mm thick foam underlay provides under-carpet insulation for maximum comfort, and is specifically designed to enhance airflow with punched holes and a low TOG rating of 0.8.

Other underfloor heating underlay options for carpet include Duralay Heatflow Carpet Underlay, Duralay Durafit 650 Underlay, and Tredaire King Underlay. It’s important to note, however, that Duralay Heatflow Carpet Underlay cannot be used with electric or dry underfloor heating systems.

Generally speaking, any engineered wood underlay in this range can also be used as an underfloor heating underlay for laminate flooring, but we recommend checking the product description for more detailed information on the flooring compatibility of each sponge rubber underlay.

When it comes to underfloor heating underlay for vinyl floors, a popular product for use with luxury vinyl tile flooring is the Duralay LVT Dry Back Underlay.

For more expert advice, send an email to our sales team with your flooring details and we’ll be in touch with further guidance.

No. While you’re free to do whatever you like with your floors, we would never recommend keeping an underlay past the lifespan of the flooring it was originally installed under. Generally, underlay will degrade at a similar rate to the floor covering, so if this needs replacing, then so does the old underlay.

In the case of pulling up your flooring to install electric (dry) or hydronic (wet) underfloor heating, it’s even more important to install new underlay suitable for underfloor heating – because the old product may not be, which would decrease the efficiency of the heating system and increase your energy bills.

So, if you’re installing a new heating system, the best advice would be to install new flooring and new underfloor heating underlay at the same time.

You may want to keep your old flooring and re-lay it on top, but even so, you should invest in a specialised underlay of appropriate thickness and density for your flooring type and heating system type. Otherwise, you won’t get the most value out of your flooring and underfloor heating.

It’s recommended to use a low TOG underlay for underfloor heating because an underlay with a high Thermal Overall Grade will make it harder for warm air to pass through to the flooring all over the room. A lower TOG rating allows heat transfer at lower temperatures, reducing energy waste and heating costs.

Special low-TOG foam underlays, like ThermalStream Underlay with its 0.8 TOG rating, and sponge rubber underlays with moisture-resistant barriers, like Duralay Timbermate Excel and Silentfloor Gold, can facilitate faster heat transfer while protecting the flooring from moisture.

With our underfloor heating underlay ratings ranging from 0.1 to 1.1 TOG, it should be easy to find a solution that’s compatible with the TOG of your flooring. When combined, the total TOG rating of the floor and underlay should not exceed 2.5 TOG, so keep this in mind when choosing thicker flooring like carpet.

So, you know that to use underlay with underfloor heating, it must have a low TOG rating, especially with carpet – but what is the best underlay thickness?

The average thickness of underfloor heating underlay is around 8mm, but this typically applies to carpet underlays, which often need a bit more support to preserve the pile. Thinner underlays from around 2mm to 3mm are commonly used for wood, vinyl, or laminate flooring with loose-lay or floating installation.

You can learn more about this in our carpet underlay thickness and laminate underlay thickness guides, or contact us for advice.

The cost of delivery depends on the size/weight of your order and the delivery address. Simply Underlay can only deliver to mainland UK addresses, though we may be able to offer a quote for delivery to customers in the Scottish Highlands or Northern Ireland if you contact our customer service team.

When you add items to your basket and proceed to the checkout stage to pay, it should display an estimated delivery price for your order.

You can choose between a premium delivery service to receive your underfloor heating underlay sooner, or standard delivery to have your order delivered in 2 to 3 working days. We aim to ship in-stock orders placed before 12pm on the same working day, and deliveries cannot be changed after dispatch.

Please bear in mind that the courier will only make two kerbside delivery attempts before returning your package to us, so you must ensure that your address details are correct and that the courier can access your property to deliver your goods. For more information, please read our delivery page or website FAQs.