NZ timber & bio-materials embodied carbon (2026, EPD-sourced)
Advances RT_212 — firms the timber embodied-carbon cell; non-timber + NZD cost stay open
Timber numbers are HIGH confidence — read directly from NZ EPD result tables (pdftotext), NZ geographical scope confirmed in-PDF, and one Australian EPD (XLam) caught during verification and excluded. Non-timber bio-materials (hempcrete/straw/wool/cellulose) have no published NZ per-material data — the BRANZ CO2NSTRUCT V2.0 spreadsheet (JS-gated) is the identified next source. AI-prepared → page data_quality medium (timber claim high within-claim).
Summary
NZ-specific cradle-to-gate (A1–A3) embodied carbon for structural timber — the modelled bio-material. Using GWP-fossil (GWP-total is strongly negative because EPDs bundle ~−800 kgCO₂e/m³ of stored biogenic carbon, a credit only if carbon storage is actually modelled): sawn radiata KD 51.3, sawn KD softwood (CHH) 80.4, LVL 91.4, CLT 128, glulam 136 kgCO₂e/m³. Treated-timber adds a surcharge (Boron +2 → LOSP +50 kgCO₂e/m³). The non-timber bio-materials (hempcrete, straw-bale, sheep-wool, cellulose) have no published NZ per-material figure — only international values exist, and the NZ factors sit in the BRANZ CO2NSTRUCT V2.0 / NECO2 spreadsheet (not machine-openable). Material cost data is weak/dated.
Key claims
- claim: "STRUCTURAL TIMBER — NZ EPD A1–A3 GWP-fossil (EPD-read, HIGH). Sawn radiata KD (Techlam/WPMA) 51.3 kgCO2e/m³ (0.105/kg, density 488); sawn KD softwood (CHH) 80.4 (0.155/kg, 520); LVL untreated (CHH Futurebuild) 91.4 (0.150/kg, 609); CLT (Techlam/WPMA) 128 (0.256/kg, 500); glulam (Techlam/WPMA) 136 (0.28/kg, 491). Use GWP-fossil for cradle-to-gate manufacturing; GWP-total is strongly negative (bundles ~−800 kgCO2e/m³ biogenic carbon — credit ONLY if carbon storage is modelled). Treated-timber surcharges (Techlam, additive kgCO2e/m³): Boron +2, H3 CCA +16–20, H4 CCA +24–28, LOSP +50. Glulam 0.28 kgCO2e/kg matches the Green Star / SESOC reference. Read directly from NZ EPD result tables via pdftotext; NZ geographical scope confirmed in-PDF."
source_location: "Techlam/WPMA Radiata EPD S-P-00997; CHH Timber EPD; CHH Futurebuild LVL EPD S-P-05514; Techlam CLT + Glulam EPDs — result tables"
- claim: "AUSTRALIAN EPD EXCLUDED (provenance rigor). The XLam CLT EPD (−293 GWP-total / 447 density @ 480 kg/m³) is an Australian product (Wodonga VIC; 'Geographical scope: Australia') — caught during verification and excluded from the NZ set. Use Techlam CLT (128 kgCO2e/m³ GWP-fossil) as the NZ CLT figure."
source_location: "XLam CLT EPD (Australia) vs Techlam CLT EPD (NZ)"
- claim: "NON-TIMBER BIO-MATERIALS — no NZ per-material data (gap). No published NZ per-material kgCO2e exists for hempcrete, straw-bale, sheep-wool or cellulose insulation. BRANZ ER105 (2025) treats them qualitatively (hempcrete 'carbon-neutral to carbon-negative'); Terra Lana (main NZ wool insulator) holds a Declare label, NOT a quantified EPD. Only INTERNATIONAL figures exist: straw-bale wall A1–A3 −101 to −147 kgCO2e/m³ (Santamaria-Herrera 2025, review of 12 European EPDs); sheep-wool insulation ~0.8–1.5 kgCO2e/m² per inch (international). The NZ per-material factors are held in the BRANZ CO2NSTRUCT V2.0 / NECO2 spreadsheet (neco2.co.nz / BRANZ low-carbon-tools), which is JS-gated and could not be machine-opened."
source_location: "BRANZ ER105 (2025); Santamaria-Herrera 2025; Terra Lana Declare label; CO2NSTRUCT V2.0 not openable"
- claim: "COST — weak/dated (stays a gap). No current NZD material rates for hempcrete/wool/CLT were located. Dated/indicative only: natural-material build ~NZD 2,000–3,000/m² (Hemp Technologies NZ, undated); owner-built straw-bale ~NZD 1,500/m² (Australasian forum) vs a standard NZ build NZD 3,500–5,500/m². Not usable as a model cost cell."
source_location: "Hemp Technologies NZ (undated); Australasian straw-bale forum; standard NZ build-cost range"Neobiome Intelligence relevance
Advances RT_212 — firms the timber embodied-carbon cell for the D04 low-carbon-construction materials lever (timber is the modelled bio-material). Structural-timber GWP-fossil is now EPD-sourced by product (51.3 radiata → 136 glulam kgCO₂e/m³), which is what the materials lever needs; the GWP-fossil vs GWP-total distinction is load-bearing — the ~−800 kgCO₂e/m³ biogenic figure is a storage credit, not a manufacturing emission, and must not be double-counted unless carbon storage is explicitly modelled. The non-timber bio-materials and all NZD material costs stay open → RT_212 stays open, with the BRANZ CO2NSTRUCT V2.0 spreadsheet identified as the single best next source (raised as RT_298). Feeds low_carbon_construction + D04.
Retrieval provenance
AI-prepared deep research, 2026-06-20, reading NZ EPD PDFs directly (pdftotext) + WebSearch. Timber = HIGH (read from EPD result tables, spot-verified, NZ scope confirmed in-PDF; the verification pass caught and excluded an Australian EPD). Non-timber + cost = weak (no NZ data / dated). Values re-confirmable against the fetchable EPD PDFs before applying to a model cell.
Research targets
Documents to retrieve
- RT_298 — BRANZ CO2NSTRUCT V2.0 / NECO2 spreadsheet (neco2.co.nz / BRANZ low-carbon-tools): the NZ per-material embodied-carbon factors for the non-timber bio-materials (hempcrete/straw/wool/cellulose). JS-gated, needs a manual download. The single best next source for the RT_212 non-timber gap.
Research gaps
- RT_212 stays open: non-timber bio-material NZ embodied carbon (→ RT_298) + NZD installed-cost rates for the bio-materials (no current NZ rates located).
Connections
Links to
Concepts (1): Low-Carbon & Bio-Based Construction
EDT domains (1): D04: Sustainable Habitat & Building Technology
Referenced by
Sources (4): OT_093 · OT_123 · OT_134 · OT_158
Concepts (1): Low-Carbon & Bio-Based Construction
EDT domains (1): D04: Sustainable Habitat & Building Technology