Flax Insulation.
Hemp insulation has a negative CO₂ footprint — it is carbon-neutral and biodegradable. An obvious choice for those who want to minimise a building's climate impact, even though the price is higher. Read the numbers together with function, lifespan, detailing and the specific building element.
- Carbon Footprint (GWP)
- −0.56 kg CO₂-eq/kg
- Source: estimatee based on the EN 15804 average
- Density
- 20–40 kg/m³
- Expected Lifespan
- 50+ years (when installed correctly)
How to use this assessment
The assessment of flax 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 flax insulation?
Flax insulation is made from natural fibres from the flax plant. It is one of the few insulation materials with a negative carbon footprint — the plant absorbs CO₂ as it grows. It is vapour-permeable, biodegradable, and contains no synthetic chemicals. A premium alternative to mineral and synthetic insulation.
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 Rafter bays and roof insulation
- check_circle Exterior walls in lightweight construction
- check_circle Interior partitions
- check_circle Floors in timber structures
In Renovation
Flax insulation is ideal for renovation of older timber structures and half-timbered houses where you want to preserve the structure's vapour permeability and avoid moisture problems.
Questions about flax insulation
Is flax insulation durable?
Yes, when correctly installed in ventilated, vapour-open structures, flax insulation lasts 50+ years. It is important to avoid permanent moisture accumulation, but flax's natural hygroscopy helps regulate moisture.
Is it more expensive than mineral wool?
Flax insulation typically costs 2–3x more than mineral wool. It is a premium product. The price is partially offset by lower carbon footprint, better work environment during installation (no fibres), and biodegradation at end of life.
Does flax insulation require fire treatment?
Yes, flax-based insulations are normally fire-treated with borates (same as cellulose insulation) to meet fire requirements. This does not significantly alter the material's natural properties.
Can it be used in all construction types?
Flax insulation is best suited for vapour-open, lightweight timber structures. It is not suitable for moist structures such as basements and inverted roof terraces.
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