Source
https://www.branz.co.nz/pubs/research-reports/er105/ — original source (opens in a new tab; the file is not redistributed)
Summary
BRANZ External Research Report ER105 (Petrović et al., 2025) examines the opportunities and barriers to adopting bio-based building materials — timber, hempcrete, straw structural insulated panels, mycelium biocomposites, wool and others — in New Zealand construction. Drawing on a literature review and 35 stakeholder interviews, it argues that bio-materials can drive radical decarbonisation of the built environment (with health co-benefits) but face real barriers of cost, knowledge, supply-scaling and a conservative industry. It is a strategy and transition study, not a materials-data report: it carries no embodied-carbon or cost figures, but it maps the NZ bio-material landscape, the drivers/barriers/enablers, the food-vs-materials land tension, and the Wai262/Māori-kaitiaki dimension. For Neobiome Intelligence it is the anchor for a low-carbon-construction concept and the framing for treating building materials (not just operational energy) as a decarbonisation lever in habitat design.
Key claims
- claim: "ER105 (Petrović et al., Victoria University of Wellington, 2025) examines adopting bio-materials in NZ construction, supported by a literature review and 35 semi-structured stakeholder interviews (bio-material innovators, architects, designers, builders, researchers, policymakers; predominantly NZ plus some international leaders); it presents 17 targeted recommendations for a bioeconomy transition in construction."
source_location: "Abstract; Executive summary; methods"
- claim: "Bio-materials have the potential to drive radical decarbonisation, with estimated emission reductions of up to 40% by 2060 in many regions, alongside psychophysiological (health and wellbeing) benefits; direct hands-on experience of the materials is important both for understanding them and for realising those wellbeing benefits."
source_location: "Executive summary (p.4)"
- claim: "Bio-materials are available today for all types of architectural application — structural components, building envelope, services, interior fit-outs, furnishings and landscaping (the 'building materials biocircle', Figure 6). The NZ palette includes timber, hempcrete, straw structural insulated panels (SIPs), mycelium biocomposites and wool."
source_location: "Executive summary (p.4); Figures 1, 3, 4, 6"
- claim: "Increased bio-material use could raise demand for agricultural land and create supply bottlenecks; the transition should align with agroecological principles — supporting biodiversity and avoiding competition with food production and climate mitigation. The intersection with agriculture currently contributes to inaccuracies in life-cycle assessment (LCA) calculations for bio-materials."
source_location: "Executive summary (p.4)"
- claim: "Recognition of Māori as kaitiaki under Wai262 is foundational to ethical engagement with bio-materials; bio-material investment should consider partnerships with Māori-owned opportunities grounded in Te Ao Māori and driven by iwi and hapū whanaungatanga."
source_location: "Executive summary (pp.4–5)"
- claim: "The 35 interviews identified 3 key drivers (people prefer natural/bio-based materials; growing interest; clients are asking for them) and 7 key barriers (limited public knowledge; stigmatisation; unclear who bears the risk of early applications; higher perceived or real cost; greenwashing enabled by the externalised costs of conventional materials; difficulty scaling NZ supply/production; a conservative, entrenched incumbent industry), with enablers centred on hands-on experience, professional guidelines and supportive policy."
source_location: "Executive summary (pp.5–6); Drivers/Barriers/Enablers sections"Neobiome Intelligence relevance
- D04 — materials as a decarbonisation lever (new concept). Beyond operational energy (HEEP/H1) and the structural envelope, ER105 establishes building materials themselves — bio-based, low-embodied-carbon — as a habitat decarbonisation strand (up to 40% emission reduction potential), with health co-benefits OT_045. Anchors the low_carbon_construction concept page.
- D04 ↔ D07/I07 — the food-vs-materials land tension. For a self-sufficient community this is the critical caveat: scaling bio-materials (hemp, straw, timber) competes for the same land as food production, so a Neobiome design must allocate land across food, energy (agro-PV) and materials under agroecological principles, not optimise materials in isolation OT_045.
- Governance / Māori partnership (thesis + NI). The Wai262 kaitiaki framing makes Māori-owned, Te Ao Māori-grounded supply a foundational design consideration for a NZ community’s material sourcing OT_045.
- ⚠ Scope: qualitative strategy report — no embodied-carbon (kgCO₂/m²) or cost figures; cost is named as a barrier. Those numbers stay a gap (new RT) and would come from EPDs / Bulletin 679 / LCA datasets.
Research targets
Research gaps
- NZ embodied-carbon (kgCO₂e/m² or per-element) and installed-cost data for the main bio-materials (timber, hempcrete, straw SIPs, mycelium, wool) — ER105 establishes the case qualitatively but carries no numbers; needed before low-carbon materials can be costed/quantified in the model.
- A land-allocation rule for a self-sufficient community across food, energy (agro-PV) and bio-materials under agroecological constraints — the D04↔D07 coupling ER105 flags but does not quantify.
Connections
Links to
Concepts (1): Low-Carbon & Bio-Based Construction
Referenced by
Sources (4): OT_049 · OT_051 · OT_123 · OT_134
Concepts (2): Healthy Housing — Warmth, Dryness & Wellbeing · Low-Carbon & Bio-Based Construction
EDT domains (1): D04: Sustainable Habitat & Building Technology