Fastwarm® 20mm XPS Insulation Boards provide excellent thermal insulation while offering a thicker profile for projects that require superior energy efficiency. Ideal for underfloor heating on concrete or screeded bases where build-up height is less of a concern.
Strong, lightweight, and easy to install, these boards deliver robust insulation and sound reduction for both tiled and floating floor finishes.
- Approved by Ultra Tile – Fully compatible with flexible adhesives.
- Exceptional Thermal Properties – Thermal conductivity of just 0.031 W/mK.
- Mid-Range Thickness – 20mm depth adds insulation without bulk.
- Improved Acoustic Insulation – Ideal for multi-floor properties.
- Trim Easily on Site – No specialist tools needed.
- Standard Dimensions – 1200mm x 600mm boards (0.72m² coverage).
- Reliable Strength – Supports loads up to 30 tonnes per m².
Installation Guidance
The Fastwarm® XPS insulation boards can be used beneath both tiled flooring and floating floor installations (such as laminate or engineered wood). However, installation methods will vary depending on the type of flooring and subfloor surface.
Undertile Installations:
Fix boards to the subfloor using a suitable flexible tile adhesive. When tiling over a timber subfloor, we recommend using our dedicated Fastwarm® Tile Backer Boards, which can be mechanically fixed in addition to being bonded with flexible adhesive.
Underwood Installations:
Lay the XPS insulation boards directly onto a clean, dry, and level subfloor in a brickbond pattern. Secure the joints using our heat-resistant Fastwarm® Duct Tape for added stability beneath floating floor finishes.
Please note: Boards are supplied in black. Blue colour shown in some images is for illustration only.
Choose the ideal board thickness to suit your project's build-up and insulation needs: 6mm | 10mm | 30mm | 50mm
| Thickness | 6mm, 10mm, 20mm, 30mm & 50mm |
|---|---|
| Board Dimension | 1200mm x 600mm |
| Material Type | Expanded Polystyrene |
| Thermal Conductivity | 0.031 W/mk |
| Material Density | 33 kg/m3 |
| Compressive Strength | 30 t/m2 |
| Moisture Absorption | < 0.1 vol % |
| Euroclass Fire Rating | E Euroclass |
Delivery Options
2-3 working day delivery
Next working day
Next working day before 10:30
Saturday Delivery
Delivery cut off times
Our daily cut-off time for dispatch is 4:30pm Monday–Thursday and 4:00pm on Fridays. Orders placed before the cut-off time will be dispatched for next working day delivery (if this option is selected). Orders placed after 4:00pm on Friday will be dispatched on Monday for Tuesday delivery.
Bank holidays may affect these delivery times, so please contact our team if unsure on 01268 744479
Other Delivery Options
PRE-10:30AM and Saturday Delivery services are available, but orders must be placed before the relevant cut-off times.
NOTE: All orders placed on a Friday will be delivered on the following Monday (unless its a bank holiday), unless a Saturday Delivery service is selected and paid for before the 4:00pm Friday cut-off.
Delivery outside the UK
Delivery outside mainland UK may be arranged by prior agreement. You will be advised of the delivery charge before dispatch, at which point you can decide whether you wish to proceed with your order.
Important: Our deliveries rely on third party couriers, so, whilst we make every effort to deliver your order on the specified date and time, unfortunately there may be occasions when this will not be possible due to external influences. Due to this we strongly recommend you ensure you have received your order before any tradespeople/builders are scheduled to commence work.
Still Unsure? Talk to an expert
If you need any guidance or further information our highly experienced team are on hand to help.
Get in touch using our contact form or give us a call on 0800 023 4203 or 01268 744 479.
