What is concrete floor insulation?
Concrete floor insulation involves adding a thermal barrier above or below a solid concrete slab to prevent heat loss and improve indoor comfort. Because concrete is dense and highly conductive, it can quickly absorb and lose heat, making uninsulated floors feel cold underfoot and driving up energy bills.
Why concrete floors lose heat
Concrete has a high thermal mass, meaning it absorbs and transfers heat easily. In winter, heat escapes through the slab into the ground, while in summer, the slab can hold unwanted warmth. Without insulation, up to 15% of a home’s heat can be lost through the floor, significantly impacting your EPC rating and overall energy efficiency.
Benefits of concrete floor insulation
Thermal efficiency and reduced energy bills
By adding insulation, heat loss through the slab is minimised, cutting energy bills and reducing household carbon emissions. This is especially valuable for homeowners aiming to improve EPC ratings or meet UK retrofit standards.
Improved comfort in winter and summer
Insulated concrete floors remain warmer underfoot in winter and cooler in summer, creating a more consistent and comfortable indoor climate.
Noise reduction and acoustic benefits
Concrete floor insulation can also dampen airborne and impact noise, which is beneficial in flats, conversions, or multi-storey homes.
Protection against damp and moisture
Properly installed insulation creates a barrier that prevents condensation and damp from penetrating the living space. Not only does this help conserve heat, but it also protects flooring finishes and indoor air quality.
Types of concrete floor insulation
Rigid insulation boards
Rigid boards are the most common choice, but there are several different types to choose from:
- PIR (polyisocyanurate) boards: excellent thermal resistance, thin but highly effective.
- XPS (extruded polystyrene) boards: durable, moisture-resistant, ideal for basements.
- EPS (expanded polystyrene) boards: cost-effective, lightweight, suitable for large areas.
Concrete floor insulation rolls
Mineral wool or fibreglass rolls can be installed above concrete slabs under floating floors. They provide thermal and acoustic benefits but usually require a vapour control layer to avoid damp.
Foil-backed and reflective insulation
Foil-backed layers are often combined with underfloor heating systems. They reflect heat upward into the room, improving efficiency.
Eco-friendly and sustainable options
Sheep’s wool, hemp, and recycled fibre boards are sustainable alternatives, offering good thermal performance and a lower carbon footprint.
Concrete floor insulation for different applications
New build concrete floors
In new builds, insulation is typically laid over the slab before screed or flooring is added, ensuring compliance with UK building regulations (Part L).
Existing concrete floors (retrofit insulation)
For retrofits, insulation is usually installed on top of the slab as a “floating floor” system. This may raise floor levels slightly but avoids major structural work.
Concrete floors with underfloor heating
Insulation beneath underfloor heating ensures heat is directed upwards, maximising system efficiency and reducing wasted energy.
Basement and ground-level insulation
Basements are prone to damp and heat loss. XPS boards are particularly suited for below-ground use due to their high moisture resistance.
Concrete floor insulation vs other insulation methods
Concrete floor insulation vs suspended floor insulation
- Concrete floors require rigid or surface insulation.
- Suspended timber floors use mineral wool or rolls between joists.
- Concrete insulation tends to be more durable but also more disruptive to install.
Concrete floor insulation vs underlay
Standard underlay provides minimal thermal benefit compared to proper insulation. Insulation rolls or boards should always be prioritised for energy efficiency.
Rigid boards vs rolls
Rigid boards generally outperform rolls for concrete floors due to their compressive strength, making them suitable under screed, tiles, or laminate.
How to install concrete floor insulation
Tools and materials required
- Rigid boards or rolls.
- Vapour control layer (if needed).
- Adhesives or fixing systems.
- Cutting tools, tape, PPE.
Step-by-step installation guide
- Clean and level the existing slab.
- Lay a damp-proof membrane (DPM).
- Fit insulation boards or rolls.
- Install a vapour barrier if required.
- Add screed or floating floor finish.
DIY vs professional installation
DIY may be possible for small areas, but professional installation is recommended for retrofits, basements, or homes with underfloor heating to ensure compliance and avoid damp issues.
Cost of concrete floor insulation
Average price per m²
Concrete floor insulation with professional installation typically costs £35–£90 per m², depending on the material (EPS being the cheapest, PIR being the most expensive). With the higher cost particularly for retrofits requiring floor levelling or new screed.
Long-term savings and payback period
Energy savings can amount to £150–£300 annually, meaning insulation often pays for itself within five to 10 years, alongside increasing property value and EPC performance.
Best materials for concrete floor insulation
PIR boards
Excellent thermal efficiency with thin layers, ideal for homes with limited headroom.
XPS boards
Moisture-resistant and strong, best for basements and ground-level slabs.
Mineral wool rolls
Good for floating floors where acoustic insulation is also required.
Composite insulation solutions
Combine rigid boards with reflective foils for maximum thermal and moisture protection.
Where to buy concrete floor insulations
When buying concrete floor insulations, you’ll usually compare three types of suppliers: DIY retailers, specialist insulation stores, and professional installers. Each option has different benefits depending on whether you’re a homeowner tackling a small project or a property developer managing large-scale installations.
| Supplier Type | Example Retailers | Best For | Pros | Cons |
| DIY & General Retailers | B&Q, Wickes, Screwfix | Small home projects, DIYers | Easy to access, affordable, wide range of basic PIR/XPS/EPS boards | Limited technical advice, not always best for large projects |
| Specialist Insulation Suppliers | Insulation Superstore, Online Insulation | Contractors, architects, developers | Wide product range (including eco-friendly options), technical datasheets, and bulk discounts | Delivery costs can add up, and may require trade accounts |
| Professional Installers | Eco Insulation (recommended) | Homeowners wanting hassle-free installation | Supply + install, advice on building regs, EPC improvements, warranties | Higher upfront cost compared to a DIY purchase |
Which option should you choose?
- Homeowners on a budget: Consider DIY boards from B&Q or Wickes if you’re confident in installing yourself.
- Builders or contractors: Go through specialist suppliers to access bulk deals and technical support.
- Property owners upgrading EPC ratings: A professional installer like Eco Insulation ensures the job is compliant, high-quality, and optimised for long-term energy savings.
Is a concrete floor insulation worth it?
Whether for a retrofit or new build, concrete floor insulation reduces energy bills, improves comfort, and enhances EPC ratings. With options ranging from cost-effective EPS boards to sustainable eco-products, it offers strong long-term value and contributes to a warmer, healthier, and more energy-efficient home.
Get in touch with Eco Insulation to learn more, receive a quote, and book your installation today.