No — polished concrete is not cold, and the idea that it is comes from touching bare, unheated concrete in old buildings. A modern polished concrete floor installed over underfloor heating (UFH) is one of the warmest, most comfortable floors you can have. Here’s the science, and the truth.
Where Does the “Cold Floor” Myth Come From?
The reputation for coldness comes from two places. First, bare concrete in unheated environments — garages, cellars, old factory floors — genuinely is cold to the touch. Second, concrete feels colder than carpet even at the same temperature, because it conducts heat away from your feet faster than soft flooring.
But neither of those situations applies to a well-installed, heated polished concrete floor in a London home. When your floor is warm, concrete holds and radiates that warmth exceptionally well. That’s thermal mass — and it’s a feature, not a bug.
What Is Thermal Mass and Why Does It Matter?
Thermal mass refers to a material’s ability to absorb, store, and release heat slowly. Concrete has high thermal mass — it soaks up heat energy and releases it gradually over time.
This means:
- Your UFH system doesn’t have to work as hard once the floor is up to temperature
- The floor stays warm for hours even after the heating switches off
- Temperature fluctuations are reduced — the floor acts as a heat battery
- Energy bills can be lower compared to quickly-cooling low-mass floors
Compare this to timber or LVT, which have low thermal mass — they respond quickly to heating but cool down just as fast when the system turns off.
Polished Concrete and Underfloor Heating: A Perfect Match
Polished concrete is genuinely one of the best floor types for underfloor heating systems. Here’s why:
- Low thermal resistance: A 5–8mm overlay has very low tog value, meaning heat transfers through it efficiently
- Seamless coverage: No grout joints, no gaps — the entire floor surface conducts heat evenly
- Thermal retention: Once warm, the floor stays warm. Your UFH runs in longer, lower cycles rather than sharp on/off bursts
- Compatible with both wet and electric UFH: Works with hydronic systems (pipes in screed) and electric mat systems
At LFS Polished Concrete, we install 5–8mm overlays specifically designed to work over existing UFH systems in London homes. The thinness of the overlay means you get all the thermal benefits without raising your floor height significantly.
How Warm Does It Actually Get?
With a properly commissioned UFH system, your polished concrete floor surface will typically reach 22–26°C — comfortably warm underfoot. Most systems are designed to run with a floor surface temperature of around 24°C, which feels pleasantly warm rather than hot.
The key is that UFH is a low and slow heat source. It works best when set to run consistently at a moderate temperature rather than blasting heat in short bursts. Polished concrete is ideal for this pattern because of its thermal mass.
Tips for Keeping Your Polished Concrete Floor Warm
- Use a programmable or smart thermostat — allow the floor to warm up gradually before you wake up or come home. Don’t try to heat it quickly from cold.
- Don’t turn the heating off completely in cold weather — it takes longer to reheat a high-mass floor than a timber one. Keep it ticking over.
- Insulate underneath — if you’re on a ground floor slab, good insulation below the UFH pipes makes a dramatic difference to efficiency.
- Add rugs if needed — there’s no reason you can’t add a rug to sitting areas. It won’t harm the floor and adds softness underfoot.
- Commission your UFH properly — ensure your heating engineer sets the correct flow temperature and timings for a concrete floor. It’s different from timber.
What About Rooms Without UFH?
If you’re installing polished concrete in a room without underfloor heating, it will be cooler underfoot than a carpeted floor — just like any hard flooring. In these situations:
- Polished concrete in hallways, living rooms, and kitchens is still perfectly comfortable with socks or slippers
- Area rugs in seating areas add warmth and comfort
- The floor won’t be cold in a heated room — it will be room temperature, which is fine
The only time polished concrete genuinely feels cold is in an unheated room in winter — which applies to every hard floor, not just concrete.
Frequently Asked Questions
Is polished concrete cold in winter?
Not with underfloor heating. With a good UFH system running, polished concrete reaches 22–26°C surface temperature and stays warm for hours after the heating cycles off. Without heating, it will feel cool — as any hard floor would.
Can polished concrete be installed over existing underfloor heating?
Yes — this is one of our most common installations. A 5–8mm polished concrete overlay can go directly over an existing UFH screed. The thin overlay has low thermal resistance and doesn’t significantly impede heat transfer.
Does polished concrete work with electric underfloor heating?
Yes. Electric mat systems work well under polished concrete overlays. The low thermal resistance of the overlay means heat reaches the surface efficiently. Always confirm with your heating engineer and follow manufacturer guidelines for maximum floor temperature.
Is polished concrete warmer than tiles?
At the same temperature, polished concrete and porcelain tiles feel similar underfoot — both are hard surfaces with moderate thermal conductivity. The real advantage of concrete is its higher thermal mass, which means it holds heat longer and creates more even, stable warmth.
How long does it take for polished concrete to heat up?
Longer than timber or LVT — typically 2–4 hours to reach full surface temperature from cold, depending on the system and insulation. This is why we recommend running UFH on a consistent schedule rather than on-demand. Once up to temperature, it stays there efficiently.
Thinking about polished concrete with underfloor heating in your London home? We install 5–8mm polished concrete overlays across London and the South East. Call us on 07730 584 748 or email londonflowscreed@gmail.com for expert advice and a free quote.