Underfloor heating is becoming increasingly popular in modern homes and renovations, offering a comfortable and energy-efficient alternative to traditional heating systems. However, to get the most out of underfloor heating, one essential component must not be overlooked — insulation boards.

Underfloor heating insulation boards play a crucial role in ensuring the system performs efficiently, safely, and cost-effectively. In this blog, we'll cover everything you need to know about these important boards — what they are, why they matter, and how to choose the right type for your project.

What Are Underfloor Heating Insulation Boards?

Underfloor heating insulation boards are designed to be laid beneath or in conjunction with underfloor heating systems — whether electric or water-based. Our primary purpose is to prevent heat loss by creating a thermal barrier between the heating system and the subfloor. This means that the heat is directed upwards into the room rather than being absorbed into the floor structure below.

These boards are typically made from high-performance insulation materials such as:

  • Extruded Polystyrene (XPS)

  • Expanded Polystyrene (EPS)

  • Polyurethane (PUR) or Polyisocyanurate (PIR) foam

  • Fibre-reinforced cement boards

  • Foil-faced insulation boards

Each type has its own characteristics, benefits, and suitability for different flooring and heating systems.

Why Are Insulation Boards Important?

1. Improved Energy Efficiency

The most immediate benefit of using insulation underfloor heating boards is improved energy efficiency. Without them, a significant amount of the generated heat could escape downwards, especially in properties with poorly insulated ground floors. By installing insulation boards, the heat is directed upwards, ensuring more of it reaches your living space — where it's needed most.

2. Faster Heat-Up Times

Insulation boards help to reduce the time it takes for the underfloor heating system to warm up a room. As the heat isn't being wasted in the subfloor, rooms reach the desired temperature more quickly. This not only adds to comfort but also reduces the workload on the heating system, contributing to a longer system lifespan.

3. Lower Running Costs

Greater efficiency means reduced energy usage. With insulation boards in place, your heating system will need less power to maintain a comfortable temperature, resulting in lower energy bills. Over time, this saving can be significant — easily justifying the initial investment in insulation.

4. Better Floor Protection and Support

Many insulation boards also provide structural support, helping to reinforce the floor and protect heating elements from impact damage or pressure from above. This is particularly important when using tiles or heavy flooring materials.

Where and How Are Insulation Boards Installed?

Insulation boards can be used with both electric and water underfloor heating systems. We are generally installed directly beneath the heating pipes or mats. In some cases, such as retrofit projects, low-profile insulation boards can be placed above the existing floor surface without requiring a full excavation.

Here's a general installation process:

  1. Prepare the Subfloor: Ensure the floor is clean, level, and dry.

  2. Lay the Boards: Fit the insulation boards tightly together, staggering the joints where possible.

  3. Fix in Place: Depending on the board type, use tile adhesive, mechanical fixings, or an adhesive-backed option.

  4. Install Heating System: Lay your underfloor heating pipes or mats on top of the insulation layer.

  5. Apply Floor Finish: Finally, install your desired floor covering — tiles, wood, laminate, etc.

Always follow manufacturer guidelines for both insulation and heating system installation to ensure safety and performance.

Choosing the Right Insulation Board

There are various types of insulation boards, each suited to different applications:

1. Tile Backer Boards

These are ideal for use with tiled floors and offer excellent thermal insulation. Many are also waterproof, making them suitable for bathrooms and wet rooms.

2. Foil-Faced Boards

Often used with electric systems, these boards have a reflective foil surface that helps bounce radiant heat back into the room.

3. High-Density XPS or EPS Boards

Lightweight and easy to install, these are suitable for use under a variety of floor finishes and are a popular all-round choice for domestic projects.

4. Fibre Cement Boards

Heavier and more rigid, these boards provide added durability and support, especially for heavier floor coverings or commercial applications.

When selecting insulation boards, consider the following:

  • Floor type and finish

  • Room usage (e.g. bathroom vs living room)

  • Subfloor material (concrete, timber, etc.)

  • Available floor height/depth

  • Type of underfloor heating system

Are Insulation Boards Always Necessary?

While some newer homes with high-quality floor insulation may not require additional insulation boards, in most cases they are strongly recommended — particularly in older properties or on ground floors. Even in well-insulated homes, boards can still improve efficiency and heat distribution.

In renovation or retrofit projects, insulation boards are particularly valuable as they help to compensate for heat loss in areas where full subfloor insulation isn't practical.

Final Thoughts

Underfloor heating insulation boards may not be the most glamorous part of your heating system, but they are undoubtedly one of the most important. We ensure that your system runs efficiently, heats your home faster, reduces your energy bills, and lasts longer.

Whether you're building a new home, renovating a single room, or retrofitting underfloor heating into an existing space, choosing the right insulation boards is a decision that will significantly impact your comfort and energy efficiency for years to come.

So, when planning your underfloor heating system, don't cut corners — give insulation boards the attention they deserve. Your future self (and your energy bills) will thank you.