Cork Insulation.
Cork has a GWP of approx. -2.0 kg CO₂-eq/kg — the cork oak absorbs CO₂ during growth, and production requires minimal energy (steam pressing without binder). Cork oak plantations in the Mediterranean are also important carbon stores and biodiversity hotspots. Read the numbers together with function, lifespan, detailing and the specific building element.
- Carbon Footprint (GWP)
- −2 kg CO₂-eq/kg
- Source: BUILD Report 2022:09 / Realdania
- Density
- 100–180 kg/m³ (ekspanderet kork)
- Expected Lifespan
- 75+ years (cork degrades very slowly)
How to use this assessment
The assessment of cork insulation is a first decision basis. Carbon numbers, density and lifespan give a point of comparison, but the material must always be read together with structure, moisture, fire requirements, detailing, maintenance and the condition of the existing building. A good material choice is therefore both a data question and an architectural judgement. The useful next step is to clarify which questions should be examined further before the material is specified in a project.
What is cork insulation?
Cork is the bark of the cork oak (Quercus suber), harvested without felling the tree — the bark regrows over 9–12 years. Expanded cork is produced by steam heating without added binder: cork's natural resin (suberin) bonds the granules. Cork is naturally moisture-resistant, has high thermal mass and is one of the most durable bio-based insulation materials. It is used as insulation boards, facade insulation, floor underlay and thermal breaks.
Carbon Footprint Compared
Negative carbon footprint (green) indicates carbon storage. Data based on EPD averages from ECO Platform and estimates per EN 15804.
Typical Applications
- check_circle Facade insulation (external boards)
- check_circle Floor insulation and underlay
- check_circle Thermal breaks in foundations
- check_circle Roof insulation (flat and pitched roofs)
- check_circle Sound insulation (floor and wall)
In Renovation
Cork is well suited for renovation as external facade insulation (cork boards with render), floor insulation and thermal breaks. It is the only bio-based insulation material with natural moisture resistance — and thus the most versatile in structures with moderate moisture loads.
Questions about cork insulation
Can cork be used for external facade insulation?
Yes. Expanded cork boards can be mounted directly on the masonry facade and rendered over (ETICS system). It is widespread in Southern Europe and gaining ground in Northern Europe.
Is cork durable enough for floors?
Yes. Cork is used as floor underlay and flooring in hundreds of thousands of homes. It is pressure-stable, sound-dampening and comfortable to walk on. Lifespan is 30-50 years as visible flooring and even longer as underlay.
Can cork be used in basements?
Partially. Cork's natural moisture resistance (suberin) makes it more suitable for damp environments than other bio-based materials. As a thermal break in foundations and floor insulation over concrete, cork is a good choice.
Where does cork come from?
From the cork oak growing primarily in Portugal, Spain and North Africa. The bark is harvested every 9-12 years without felling the tree — cork oak plantations are thus carbon-storing forestry.
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