Source
https://www.branz.co.nz/pubs/research-reports/er89/ — original source (opens in a new tab; the file is not redistributed)
BRANZ ER89 (2024) — Climate Change Adaptation of Buildings in New Zealand: Research Prioritisation Assessment
The scoping map of what NZ does NOT yet know about climate-adapting its buildings — plus a national climate design-envelope
Authoritative BRANZ/WSP scoping study (36 pp, Oct 2024) that reviews NZ and international building-adaptation research and interviews 17 NZ stakeholders to prioritise future research. Two things for Neobiome: (1) it reproduces NIWA/MfE’s national climate-change projection envelope (Table 1 — temperature, hot days +40–300%, frosts, extreme rainfall, extreme wind +10%, snow, drought, humidity by 2040/2090 under RCP2.6–8.5), the design-basis inputs a D04 building-adaptation calc needs; and (2) its headline finding is a capability, not knowledge, gap — the costs and specific building adaptations NZ needs are “largely undefined,” and stakeholders unanimously judge NZ buildings are not climate resilient and that current new-builds won’t be resilient in 50 years, with the binding constraint being implementation not evidence. It also frames insurance retreat / uninsurability as a live systemic shock (I06). ⚠ It is a qualitative scoping/research-prioritisation study — nearly all figures are BRANZ/WSP reproducing OTHER bodies’ numbers (MfE 2016, Ipsos 2023, cited BRANZ/academic studies), not original measurement, so it is a signpost to primaries, not a data source itself.
Summary
BRANZ External Research Report ER89 (Locke & McKelvey, WSP NZ Ltd, Project LR17589, 8 October 2024) is a research-prioritisation scoping assessment commissioned by BRANZ to establish what knowledge gaps exist in adapting New Zealand buildings — the building itself: design, materials, structure and envelope — to climate change. It combines a literature review (NZ and international) with 17 semi-structured stakeholder interviews. The report’s central conclusion is that “the costs and specific adaptations to buildings that are needed for the changing climate in New Zealand are largely undefined”: a few studies quantify climate impacts at an aggregate/national level and even fewer at the individual-building level. It reproduces NIWA/MfE’s 2016 national climate-change projections (Table 1) as the design-basis envelope, and reviews the NAP (National Adaptation Plan, Aug 2022) and MBIE’s Building for Climate Change programme as the policy frame, plus the split Building Act 2004 / RMA 1991 regulatory system. The stakeholder engagement (35 contacted, 17 interviewed) produces an inductive four-theme finding — Implementation, Education & awareness, Responsibility, and Changes to future buildings — with the recurring message that ample evidence and international adaptations already exist and the real challenge is implementation, capability and political will, not knowledge. Stakeholders flag overheating in new airtight highly-insulated homes, insurance retreat / uninsurability as a systemic economic risk, managed-retreat and equity concerns, and the inadequacy of the Building Code’s 50-year minimum-standard approach. Produced by BRANZ (the NZ building-research body); context: both — it feeds D04 (building-adaptation design levers and the NZ cost/quantification gap, NI) and I06 (climate/insurance external shocks, thesis resilience). Read verbatim via pdftotext -layout; every figure quoted traces to the raw → data_quality: high (authoritative primary publication, not AI-prepared, but a qualitative scoping study reproducing others’ figures).
Key claims
- claim: "The purpose of the review is to establish what knowledge gaps exist in adapting buildings to climate change in New Zealand, focused on the adaptation needed to the building itself (design, materials, structure, envelope). Overall, the costs and specific adaptations to buildings needed for the changing climate in New Zealand are largely undefined: a few studies quantify the impacts of climate change on the design and construction of NZ buildings at an aggregate level, and even fewer provide information that can be applied to specific buildings."
source_location: "Executive Summary, p.2; Section 3 New Zealand Research, p.10"
- claim: "National climate-change projections for New Zealand (Table 1, reproduced from MfE 2016 / NIWA): MEAN TEMPERATURE rises by 2040 from +0.7 degC [RCP2.6] to +1.0 degC [RCP8.5], and by 2090 +0.7 degC to +3.0 degC (warming greatest at higher elevations and in summer/autumn). HOT DAYS (max >=25 degC) increase by 2040 40% [2.6] to 100% [8.5], and by 2090 40% to 300% [8.5]. FROSTS (min <=0 degC) decrease by 2040 30% to 50%, and by 2090 30% to 90%. Diurnal temperature range increases up to 2 degC by 2090 (RCP8.5)."
source_location: "Section 2 Climate projections, Table 1, p.7"
- claim: "Further Table 1 projections (MfE 2016 / NIWA): DRY DAYS up to 10 or more extra per year (~5% increase) by 2090 [8.5]; VERY WET DAYS more than 20% increase in the 99th-percentile daily rainfall by 2090 [8.5] in the south-west of the South Island; SNOW days reduce by 30 days or more by 2090 under RCP8.5; DROUGHT (Potential Evapotranspiration Deficit) up to 50 mm or more increase per year by 2090 [8.5]; EXTREME WIND SPEEDS up to 10% or more increase in parts of the country (most robust in the southern half of the North Island and throughout the South Island); RELATIVE HUMIDITY decrease up to 5% or more by 2090 [8.5]; SOLAR RADIATION changes generally between -5% and +5%."
source_location: "Section 2 Climate projections, Table 1, pp.7-8"
- claim: "Data collection ran over a four-week period: 35 individuals and organisations were contacted and 17 interviews took place (via Microsoft Teams, 45-70 minutes each). Interviewees spanned the Climate Change Commission, regional/district/city councils, MBIE, Insurance Council NZ, LINZ, the Climate Adaptation Platform and academics; identified gaps were community organisations and governmental organisations. Inductive thematic analysis was used."
source_location: "Section 5.1-5.2 Stakeholder engagement / Data collection, p.18"
- claim: "When asked how climate resilient New Zealand buildings are, stakeholders unanimously agreed New Zealanders are in the infancy of responding to climate change and our buildings are not climate resilient; stakeholders believed current new constructions would not be climate resilient in 50 years. Collectively stakeholders described that there is ample evidence, international learnings and examples of effective adaptations, and that the greatest challenge is in implementing adaptations and planning for construction of future climate-resilient buildings."
source_location: "Executive Summary, p.2; Section 5.3.1 The current state, p.20"
- claim: "Inductive analysis of stakeholder interviews revealed four key themes: Implementation, Education and awareness, Responsibility, and Changes to future buildings. On Implementation, stakeholders identified there is enough existing knowledge, research and examples of adaptations, yet few changes are being made; barriers are resources/funding (exacerbated by decades of industry underinvestment), a lack of political will, and siloed decision-making (the Building Act is often disconnected from the Resource Management Act and local government)."
source_location: "Section 5.4 Discussion / 5.4.1 Implementation, p.26"
- claim: "Stakeholders described the existing Building Code as inadequate to respond to climate risks. The Building Code has a 50-year design life and takes a minimal-requirement approach; given buildings are in place longer than 50 years, planning should extend past the 50-year timeframe, and there need to be incentives for going above the current minimal requirements (or the requirements need to be raised)."
source_location: "Section 5.4.4 Future building, p.29"
- claim: "Overheating is flagged as an emerging risk in new NZ buildings: houses have better insulation but there are concerns of inadequate ventilation, and overheating can occur due to temperature extremes but also due to higher levels of insulation. There is no standard within the Building Code for ventilation systems beyond extraction vents and fans in the kitchen and bathroom. MacGregor et al (2019) list overheating evidence gaps including the absence of an accepted NZ definition of overheating and internal temperature thresholds."
source_location: "Section 5.3.4 Temperature, p.24; Section 3 (MacGregor et al 2019 box), p.10"
- claim: "Insurance retreat / uninsurability is framed as a systemic economic shock: banks require insurance on a property to lend, so if insurance penetration is reduced it can deflate property and business values, and where communities have less insurance uptake there is increased liability on the Government's balance sheet. The Government currently buys properties deemed an intolerable risk, but if no adaptation action is taken it is not guaranteed this will continue. Equity issues arise as those with fewer means cannot afford to move out of, or adapt, affected homes."
source_location: "Section 5.4.2 Responsibility, pp.26-27"
- claim: "During a recent flooding event a house drifted roughly 800 m from its original site; the house had a cement foundation with polystyrene embedded as insulation, and the polystyrene made the building buoyant in the flood waters - cited by Paula Blackett (NIWA) as an example of a poor adaptation (a beneficial-for-insulation feature becoming a liability in a flood)."
source_location: "Section 5.4.2 Responsibility, p.27"
- claim: "Locke et al (2022) investigated the impact of increased wind speeds (three increases: 5%, 10% and 15%) on the design and construction costs of light timber framed buildings in New Zealand; the changes in design and construction costs corresponding to the wind-speed increases were found to be small. It was a pilot study to test the methodology given the absence of NZ information on the cost impacts of climate change on building design/construction, and its conclusions cannot be generalised (only low-rise light timber-framed buildings were considered)."
source_location: "Section 3 New Zealand Research (Locke et al 2022), p.14"
- claim: "Jalali et al (2023) used detailed thermal modelling to estimate, for different climate-change projections and NZ locations, the decrease in heating energy and increase in cooling loads: cooler NZ locations are likely to remain heating-dominated in future, but more temperate locations will switch from heating- to cooling-dominated energy use; the impact on housing design and the associated costs are not quantified. Jalali et al emphasise the localised nature of climate impacts on buildings, requiring high-resolution analyses to understand impacts in different parts of the country."
source_location: "Section 3 New Zealand Research (Jalali et al 2023), p.14"
- claim: "A recent global survey (Ipsos 2023) found that 80% of people think 'we are heading for environmental disaster unless we change our habits quickly' but only 18% of the global population view climate change as a top-three concern - cited as evidence that a lack of public awareness and of actionable detailed information contribute to inaction."
source_location: "Section 6.1 Knowledge gaps, p.32"
- claim: "Priorities for future research identified are: (1) understanding why New Zealanders do not act to mitigate and adapt, and the interventions that motivate action; (2) information that defines the future climate affecting NZ buildings, to allow true impacts and costs to be quantified; (3) estimating the impacts and costs of climate change on the design, construction and use of new buildings and on the use/maintenance of existing buildings; (4) re-evaluating the performance and environment buildings must deliver in the future climate (e.g. overheating limits are not set or agreed); and (5) communicating knowledge to policy makers, industry and the public."
source_location: "Executive Summary, p.3; Section 6.2 Priorities for consideration, pp.32-33"
- claim: "New Zealand's first National Adaptation Plan (NAP) was published August 2022; NAP objectives HBP1 (homes and buildings are climate resilient) and HBP2 (new/existing places planned to minimise climate risk) drive building adaptation, delivered through MBIE's Building for Climate Change programme (relevant NAP Actions 3.25, 5.7, 7.4, 7.6). NIWA is updating NZ's climate projections by downscaling the latest regional climate models to underpin regulatory change, with updated climate data scheduled for release in 2024 and 2025."
source_location: "Section 1.2 Adaptation planning in New Zealand, pp.4-5; Section 2, p.9"Relevance
context: both — this source contributes to the Neobiome Intelligence D04 habitat layer (building-adaptation design levers and the NZ quantification gap) and to the thesis I06 resilience argument (climate and insurance external shocks).
Neobiome Intelligence — D04 building-adaptation design levers and the NZ cost gap
- A national climate design-envelope, but only as reproduced secondary data. Table 1 (MfE 2016 / NIWA) gives the direction and magnitude of change a D04 building-adaptation assessment needs — by 2090 under RCP8.5, hot days up 40–300%, extreme wind up ~10%, drought PED up ~50 mm/yr, snow down 30+ days, humidity down ~5%. Useful as the design-basis frame, but ER89 explicitly signposts that NIWA’s updated downscaled projections (scheduled 2024–2025) will supersede these — so treat Table 1 as an interim national envelope, not the calibration point.
- The honest headline: NZ building-adaptation costs are largely unquantified. ER89’s core finding is that the costs and specific building adaptations NZ needs are “largely undefined” — a few aggregate/national studies, almost none applicable to a specific building. For D04 this is a scoping/gap contribution: it confirms there is no directly-usable NZ building-adaptation CapEx cell to be had from the current literature, and it names the two closest quantitative primaries — Locke et al (2022) on wind-speed→build cost (found “small”) and Jalali et al (2023) on the heating→cooling energy switch — as the doc-retrieval targets below.
- Concrete design levers flagged for hazard/temperature adaptation. Overheating in new airtight, highly-insulated homes is the most-raised risk (no Building Code ventilation standard beyond kitchen/bathroom extraction; no agreed NZ overheating threshold), with solar shading identified (via the Irish LCAH case) as the optimum future-proofing strategy; passive-solar design, eaves/overhangs, glazing optimisation, thermal mass and controlled ventilation are the adaptation menu. These are directional design guidance qualifying the D04 habitat menu for a warming climate, not costed cells. The 50-year Building-Code design life is flagged as too short given buildings persist longer.
Thesis — I06 resistance to external shocks
- A qualitative NZ baseline: buildings are not climate resilient, and the gap is capability not knowledge. Stakeholders unanimously judged NZ buildings are not climate resilient and that current new-builds won’t be resilient in 50 years, while agreeing ample evidence and international adaptations already exist — locating the resilience deficit in implementation, funding, political will and siloed governance (Building Act disconnected from the RMA). This complements the engineering resilience evidence on I06 (Interview II [INT_002], Interview III [INT_003], Interview IV [INT_004]) with a systems/governance read of why known adaptations don’t get built.
- Insurance retreat / uninsurability as a systemic shock — and a worsening one. ER89 frames uninsurability as a live economic risk (banks require insurance to lend → reduced penetration deflates property/business values → increased Government balance-sheet liability; Government currently buys intolerable-risk properties but with no guarantee it continues), with attendant managed-retreat and equity concerns. Coupled with the Table 1 intensification of hot days, extreme wind and drought, this grounds the I06 argument that hazard- and insurance-aware siting/adaptation is a resilience investment. It pairs directly with the flood/landslide exposure baseline and Building Act s71–74 siting gate in the sibling BRANZ bulletin BU701.
Research targets
Documents to retrieve
- RT_376 — Locke, N.; Carradine, D.; Shelton, R.; Capie, R.; Cenek, P. (2022) Adaptation of new buildings for climate change, BRANZ External Report ER75 — the predecessor pilot study behind ER89, and the only NZ study quantifying the design/construction COST impact of a climate variable (wind speed +5/10/15% on light-timber-framed buildings). The natural retrieval for a NZ building-adaptation CapEx signal. → D04
- RT_377 — Jalali, Z.; Shamseldin, A.Y.; Ghaffarianhoseini, A. (2023) “Impact assessment of climate change on energy performance and thermal load of residential buildings in New Zealand”, Building and Environment, doi:10.1016/j.buildenv.2023.110627 — detailed thermal modelling of the heating-demand decrease / cooling-load increase across NZ locations and the heating→cooling switch under warming; quantifies the temperature-driven energy shift that D04/energy-demand adaptation needs. → D04
- RT_378 — Bengtsson, J.; Hargreaves, R.; Page, I. (2007) Assessment of the need to adapt buildings in New Zealand to the impact of climate change, BRANZ Study Report SR179 — thermal modelling of indoor overheating/energy demand plus an economic analysis deriving optimum design features for housing in different NZ regions; the closest existing regional adaptation-optimisation dataset. → D04
Research gaps
- RT_379 — Updated NIWA downscaled regional climate projections for New Zealand (MBIE Building for Climate Change programme, scheduled 2024–2025 release), superseding the MfE (2016) Table 1 projections reproduced here — the national climate design-envelope (temperature, extreme rainfall, wind, snow, drought by region/season) that would let D04 building-adaptation impacts be quantified at site level rather than nationally. → D04
Notes
Authoritative BRANZ publication (BRANZ External Research Report ER89, © BRANZ 2024, ISSN 2423-0839; prepared by WSP NZ Ltd, Project/Contract LR17589, dated 8 October 2024), read verbatim via pdftotext -layout (36 pp report + participant-information appendix) — not AI-prepared, so no retrieval-provenance block is required. Every figure quoted traces to the raw. data_quality: high to match the corpus convention for directly-read BRANZ publications (OT_040, OT_047, the sibling BU701) and the model_design.md §2 definition. ⚠ Nearly all numbers here are ER89 reproducing other bodies’ figures (MfE 2016 Table 1, Ipsos 2023, and cited BRANZ/academic studies) rather than original measurement, so high (single authoritative primary, not independently corroborated within itself) is the more honest label for a qualitative scoping study.
⚠ Scope caveat: ER89 is a research-prioritisation / scoping study, not a data source. Its contribution is (a) the NAP/regulatory and knowledge-gap MAP of NZ building adaptation, (b) a qualitative stakeholder read of why known adaptations don’t get built, and (c) a set of pointers to the quantitative primaries (Locke 2022, Jalali 2023, Bengtsson 2007, MacGregor 2019) captured as RTs above. Do not mine Table 1 or the stakeholder quotes as if they were ER89’s own measurements.
⚠ Cross-reference — the “drifting house” figure. ER89 (§5.4.2, Paula Blackett/NIWA) reports a house drifting ~800 m in a recent flood due to a buoyant polystyrene-embedded cement foundation; the sibling BU701 reports the Esk Valley (Hawke’s Bay, Cyclone Gabrielle 2023) raft-slab house moving 600 m. These are plausibly the same underlying event described with different distances by different sources — both are retained verbatim to their own source (not reconciled); this is a soft numeric discrepancy, not an error in either page.
Cross-references: connects to BU701 (flood/landslide siting gate and exposure baseline — the quantitative complement to ER89’s qualitative shock framing), the D04 thermal-envelope/H1 evidence (OT_043, OT_057) that the overheating-in-insulated-homes finding qualifies, and the I06 engineering-resilience bullets from Interview II [INT_002] / Interview III [INT_003] / Interview IV [INT_004].
Connections
Links to
Referenced by
SSI indicators (1): I06: Resistance to External Shocks
EDT domains (1): D04: Sustainable Habitat & Building Technology