Bio-based building insulation — wood-fibre boards, hemp and flax mats, cellulose, straw, hempcrete, mycelium panels — instead of polystyrene/polyurethane foams with brominated or chlorinated flame retardants and isocyanate spray foams

Replaces: flame-retarded plastic foams and isocyanate spray foams · Scope: buildings · Evidence: high

The chemical problem#

Plastic foam insulation needs flame retardants. HBCDD was used for decades in polystyrene and is now a Stockholm Convention persistent organic pollutant (listed in 2013). Millions of tonnes of HBCDD-containing insulation remain in buildings and will become hazardous waste. PU/PIR foams contain TCPP. Spray PU foam exposes installers to isocyanates, the leading cause of occupational asthma.

Product overview#

Bio-based insulation materials in commercial use:

1. Wood-fibre boards and flexible mats (from sawmill residues): widely used in Germany, France and Switzerland; good summer heat protection (high thermal mass).
2. Cellulose insulation (recycled newspaper), blown in. Note: often treated with borates (reprotoxic classification in the EU). Choose borate-free versions (e.g. with ammonium phosphate or other treatments).
3. Hemp and flax mats, hempcrete (hemp shiv + lime binder).
4. Straw-bale and compressed-straw panels (agricultural residue).
5. Mycelium composite panels (agricultural waste bound by fungal mycelium): emerging.
6. Sheep’s wool (niche). Russia has large resources of sawmill residues, flax (historical Russian fibre crop) and straw.

Active ingredient / Composition#

Wood fibre, cellulose, hemp and flax fibres, straw, mycelium; fire treatments (lime, mineral salts); binders (bio-based or small amounts of polyolefin fibres in mats).

Key facts#

Advantages#

• No persistent brominated or chlorinated flame retardants and no isocyanates.
• Better summer comfort and acoustic performance (wood fibre).
• Stores CO₂ in buildings (carbon storage).
• Adds value to agricultural residues and sawmill by-products.

Mode of action#

Still air trapped in fibrous structures insulates. The high heat capacity of wood fibre delays heat flow in summer. Fire safety is achieved by design (cladding, char formation of dense boards) and mineral treatments.

Application#

Limitations#

• Slightly thicker walls for the same U-value; higher cost in some markets.
• Moisture design is essential (rot risk if built wrongly).
• Cellulose with borates: prefer borate-free products.

Evidence of displacement — D2: measurable displacement (minority share)#

Assessment (hand-reviewed): Minority: bio-based insulation 6.5% of the European market, 8.2% of France’s by volume (2025), 5–10% in France and Germany.

Verified figures (the number is in the quoted sentence and the sentence is on the source page):

• displacement — In France, bio-based and recycled insulation materials represented 10% of the insulation market in 2020. (France, 2020; industry association: asbp.org.uk)
• displacement — The volume of bio-based insulation sold in France increased by 87% between 2016 and 2020. (France, 2016-2020; industry association: asbp.org.uk)
• displacement — The market share of natural fibre insulation in the UK is around 1%. (UK, 2022; industry association: asbp.org.uk)
• displacement — Bio-based and recycled materials represented 10% of the French insulation market in 2020. (France, 2020; industry association: asbp.org.uk)

Suppliers — real products and services (from the vendor index)#

Companies below are active vendors in the vendor index whose own card (profile / official website) shows this product or service — matched 2026-09-28 by keyword and checked by hand against the card text. Being listed is not an endorsement; open each card for evidence, contacts and status.

Government funding signals#

Public grants for a specific technology are a leading indicator: governments fund what regulators want to replace and what is close to practical adoption. Searched on 2026-09-27 in: EU CORDIS (FP7, Horizon 2020, Horizon Europe), US federal awards (USAspending: USDA NIFA/ARS/APHIS/Forest Service, EPA, DOE, NOAA, USAID; plus NSF and NIH), UK UKRI Gateway to Research, Australian Research Council. Each grant below was reviewed by hand for relevance. China, Brazil and India are covered in the subsection below (publication-acknowledged grants). Not covered: Russia (RSF, FASIE — not reachable from the research environment) and national agencies outside these databases. Amounts are the funder’s contribution as recorded (US NIH/UKRI: per award or fiscal year).

Signal: Strong. 4 relevant grant(s) · about €18.3M in total · jurisdictions: EU.

China, Brazil, India — national research grants acknowledged in publications#

Chinese, Brazilian and Indian funders have no open grant databases reachable here, so this measures scientific papers published since 2015 that acknowledge national government grants, taken from the grant numbers publishers deposit with Crossref. Only papers whose title contains this article’s key terms are counted (a conservative lower bound; “100+” = search window full). It shows research-funding intensity, not budgets. Funders: China — NSFC, National Key R&D Program, China Agriculture Research System; Brazil — CNPq, CAPES, FAPESP, Embrapa, FAPEMIG; India — DBT, DST, ICAR, SERB, CSIR, BIRAC. Rating per country: Strong ≥50 papers · Moderate 10–49 · Weak 1–9.

Scientific evidence#

• Schiavoni S, D’Alessandro F, Bianchi F, Asdrubali F (2016). Insulation materials for the building sector: a review and comparative analysis. Renewable and Sustainable Energy Reviews 62: 988–1011.
• Asdrubali F, D’Alessandro F, Schiavoni S (2015). A review of unconventional sustainable building insulation materials. Sustainable Materials and Technologies 4: 1–17.
• Stockholm Convention (2013). Decision SC-6/13: listing of hexabromocyclododecane in Annex A.

Bioeconomy value#

Sawmill residues, straw, hemp and flax become long-lived carbon-storing building materials, replacing POP-containing petrochemical foams.