Why does cork feel warm to the touch?
Because it hardly draws any heat out of your hand. Cork is a closed-cell honeycomb that is roughly 90% trapped gas by volume, and its thermal conductivity is only about 0.045 W/m·K (expanded cork insulation board measures about 0.037 to 0.040). Stone, tile and metal pull warmth from your skin quickly and register as cold. Cork does not, so it reads as warm at the same room temperature.
Warm is about heat moving, not about temperature
A cork wall and a tiled wall in the same room are the same temperature. They feel completely different because feeling cold is really your hand losing heat. A material that carries heat away quickly feels cold. One that barely carries it at all feels warm.
Cork is mostly gas held in sealed cells, and sealed cells stop air circulating, which removes the main way heat travels through a material. That is the same property that makes thick cork a good insulator.
Where it actually matters
- On a wall, where a visitor puts a hand on it and the room reads softer than the same room in tile or stone.
- Under a glass, where cork does not chill the way a hard surface does.
- Underfoot and under the hand in a studio, where the surface is touched constantly.
An honest note about thin cork
Feeling warm and insulating are two different things, and the difference is thickness. Our wall panels are 3 mm and 4 mm. They genuinely feel warm to the hand, because that is a surface effect. They will not insulate a room, because insulation depends on depth, and at this thickness there is not enough material to do it.
We would rather say that plainly than let a specifier find out later. If you need cork that actually insulates, that is carbonised cork board, also called expanded cork, at a real thickness, and it is a different product from a decorative panel.
Common questions
Why does cork feel warm?
Because it barely conducts heat away from your skin. Cork is roughly 90% trapped gas by volume with a thermal conductivity of only about 0.045 W/m·K, so unlike stone or metal it does not pull warmth out of your hand, and it registers as warm at the same room temperature.
Is cork warmer than tile or stone?
It feels warmer, although at the same room temperature it is not actually warmer. Tile and stone conduct heat away from your hand quickly, which is what makes them feel cold. Cork conducts very little, so it feels warm to the touch.
Do thin cork wall panels insulate a room?
No. Feeling warm is a surface effect and insulation depends on thickness. Decorative cork panels of 3 to 4 mm feel warm to the hand but do not insulate a room. Insulating with cork means carbonised cork board, also called expanded cork, at a much greater thickness.
Sources
- Cork curiosities, Corticeira Amorim
- Cork: a renewable raw material (Duarte and Bordado, 2015), Frontiers in Materials
- Mortars with expanded cork (Barnat-Hunek et al., 2018), Materials (MDPI)
- The Rationale behind Cork Properties: A Review of Structure and Chemistry (Pereira, 2015), BioResources
Where to go next
- What are cork's natural properties?
- Does cork get slippery when wet?
- Does water damage cork?
- How do you clean cork?
- What is the difference between virgin, agglomerated and carbonised cork?
- Which branding method should I choose for a logo on cork?
- Is cork better than wood, acrylic or rubber for coasters?
- How is cork harvested?
- How many cork wall panels do I need per square metre?
- Is a cork yoga mat better than rubber, PVC or TPE?
- Branded cork coaster packs, priced and delivered
- How cork is harvested