Examining the Role of Regulatory Policy and Professional Practice in Selecting Sustainable Building Materials in Kaduna State, Nigeria

desirability of recycled/reclaimed content Discretionary Low — no thresholds defined None Hazardous material prohibition Explicit prohibition of asbestos; restriction of high- VOC products Mandatory High — specific substances named None specified Fire resistance Part C: fire rating requirements for structural and finish materials Mandatory High — performance ratings specified None specified Climate- responsive design General reference to climatic zones; no material- specific mandates Discretionary Low — no material specifications None Life-cycle / embodied carbon Not addressed Absent None N/A Green building certification Not addressed Absent None N/A IJEMT Policy Theme Key Provision(s) Instrument Type Specificity Level Enforcement Mechanism Financial incentives for SBMs Not addressed Absent None N/A Source: Author’s systematic document analysis, 2026 IJEMT Kaduna State Urban and Regional Planning Law 2018 Document Analysis Table 2 presents the coded analysis of the KURPL 2018 against the same thematic framework applied to the NBC. Thematic Analysis and Critical Findings The KURPL 2018 analysis reveals a planning statute, whose regulatory function that directs the process of development approval, as primarily procedural rather than substantive in relation to building material selection. Of the ten sustainability-related policy themes examined, seven are entirely absent. The Law contains no provisions referencing sustainable materials, energy-efficient specifications, recycled content, life-cycle considerations, climate- responsive construction, or financial incentives for green building practice. Its engagement with material sustainability is entirely indirect, limited to requiring that submitted building plans conform to “applicable building standards”, which is a cross-reference to the NBC. However, this provides little practical power considering the NBC’s own aspirational framing of its sustainability provisions. The KURPL 2018’s principal regulatory strength is its legal character as primary legislation enacted by the Kaduna State House of Assembly, which confers binding force and positions KADGIS as a legitimate enforcement authority. However, this institutional capacity is directed almost entirely at spatial and structural compliance, not environmental performance. The KADGIS permit review process does not apply sustainability criteria, and the EIA requirement under Part VII, while potentially relevant to material selection, provides no explicit criteria linking environmental impact findings to material specification decisions. In practice, the EIA and permit processes operate as parallel, non-integrated instruments. Comparative Gap Analysis Table 3 provides a consolidated comparative gap analysis of both instruments, identifying the key regulatory gaps that will form the basis of the Phase 2 data collection instruments. Summary of Phase 1 Findings and Transition to Phase 2 The systematic document analysis yields four principal findings that will anchor the Phase 2 instruments. 1. Sustainability provisions in both instruments are largely absent or aspirational, with no binding mandates specifically requiring the selection of sustainable building materials. 2. There is a complete absence of financial incentives, tax relief, or procurement preferences linked to sustainable materials in either instrument. 3. Enforcement mechanisms are weak or absent: the NBC has no statutory enforcement architecture at the national level, and the KURPL 2018’s KADGIS-led permit process does not systematically evaluate material sustainability. 4. Critical sustainability concepts (including life-cycle assessment, embodied carbon, and green building certification) are entirely unaddressed by either instrument. IJEMT Table 2: KURPL 2018 Coded Provisions Relevant to Sustainable Building Material Selection Policy Theme Key Provision(s) Instrument Type Specificity Level Enforcement Mechanism Building permit & plan approval Part IV: all development requires permit; plans must reference applicable building standards Mandatory Medium — defers to NBC and relevant codes KADGIS empowered to refuse/revoke permits Environmental Impact Assessment Part VII: EIAs required for large-scale development; must assess environmental consequences of construction Mandatory Low — no material-specific criteria in EIA scope KADGIS/State Environmental Agency oversight Structural / safety standards Permit conditions implicitly incorporate NBC structural requirements Mandatory (by reference) Medium — through NBC cross-reference KADGIS permit process; site inspections Local material sourcing Not addressed Absent None N/A Sustainable/green building materials Not addressed Absent None N/A Energy performance of materials Not addressed Absent None N/A Life-cycle / embodied carbon Not addressed Absent None N/A Recycled / reclaimed materials Not addressed Absent None N/A IJEMT Policy Theme Key Provision(s) Instrument Type Specificity Level Enforcement Mechanism Financial incentives for SBMs Not addressed Absent None N/A Climate- responsive construction Not addressed Absent None N/A Source: Author’s systematic document analysis, 2026 IJEMT Table 3: Comparative Regulatory Gap Analysis NBC 2019 and KURPL 2018 Regulatory Dimension NBC 2019 KURPL 2018 Implication for Phase 2 Legal enforceability of sustainability provisions Weak — ministerial directive; no Act Strong — primary legislation Ask professionals: does the NBC’s non-statutory status affect compliance behaviour? Mandatory SBM requirements Absent — all sustainability provisions discretionary Absent Ask: in the absence of mandates, what drives or suppresses SBM use? Financial incentives/disincentives for SBMs Absent Absent Ask: would financial incentives change specification decisions? What incentives are perceived as most effective? Enforcement of material specifications on site No mechanism specified Limited to permit stage; no systematic site inspection Ask: how does enforcement failure shape procurement behaviour post- permit? Definition of ‘sustainable building material’ Not defined with regulatory precision Not defined Ask: how do professionals define SBMs in the absence of regulatory definition? Life-cycle/embodied carbon provisions Completely absent Completely absent Ask: are life-cycle considerations factored into practice? Why/why not? Integration with national climate policy Limited — no formal linkage to NCCP or NDC Absent Ask: are professionals aware of/influenced by climate commitments? Green building certification pathway No national certification framework referenced Not referenced Ask: is the absence of a certification system perceived as a barrier? Source: Author’s systematic document analysis, 2026 IJEMT These four findings constitute the core of the ‘policy reality’ that Phase 2 asks professionals to respond to. Phase 2 Data Collection Instruments Semi-Structured Interview Guide The interview questions were designed to elicit in-depth elaboration on the Phase 1 regulatory findings. Each question is grounded in a specific Phase 1 gap or finding, which is noted in italics as an analytical anchor for the interviewer. The duration of the interview was approximately 45–60 minutes. Consent and audio recording were required. The following interview guide is structured under five substantive sections. Section A: Demographic and Professional Profile: The participants were registered architects, civil/structural engineers, and quantity surveyors with ≥10 years of post- qualification experience in Kaduna urban centre as shown in Table 4. Section B: Awareness and Understanding of Sustainable Building Materials Phase 1 anchor: NBC 2019 and KURPL 2018 contain no operational definition of ‘sustainable building material.’ IB1. In your day-to-day practice, how do you determine whether a building material qualifies as ‘sustainable’? Given that neither the NBC nor the KURPL defines this term, what criteria or reference points do you rely on? IB2. How would you describe the general level of awareness of sustainable building? materials among construction professionals and clients in Kaduna? What do you see as the primary knowledge gaps, and where do you think responsibility for closing those gaps lies? Findings Most participants had a working sense of what sustainable materials are but relied on their own experience rather than any regulatory definition. Ten of the fifteen interviewed said they look mainly at local availability and durability when deciding if a material is “sustainable enough.” Only three had ever referred to international frameworks like LEED or EDGE. Client awareness was described as very low across the board. P01 (Architect, 12 yrs) said: “I know what sustainable materials are in theory, but honestly there is no official guide telling me what qualifies. I go by what I have seen work.” P06 (Architect, 20 yrs) was blunter: “My clients do not ask for sustainability. They ask for cheap and fast. Until clients demand it, it will not happen.” Twelve of the fifteen interviewed also pointed to poor educational input as a major knowledge gap, this is consistent with concerns in the literature about sustainability not being adequately embedded in Nigerian professional education (Amuda-Yusuf et al., 2020). Table 4: Profile of Interview Participants ID Profession Experience Sector P01 Architect 12 yrs Private – Commercial P02 Civil Engineer 10 yrs Public / Government P03 Quantity Surveyor 15 yrs Mixed P04 Architect 11 yrs Private – Residential P05 Structural Engineer 11 yrs Private – Commercial IJEMT ID Profession Experience Sector P06 Architect 20 yrs Mixed P07 Quantity Surveyor 10 yrs Private – Residential P08 Civil Engineer 10 yrs Public / Government P09 Architect 14 yrs Private – Commercial P10 Quantity Surveyor 10 yrs Mixed P11 Structural Engineer 18 yrs Public / Government P12 Architect 12 yrs Private – Residential P13 Civil Engineer 13 yrs Mixed P14 Quantity Surveyor 18 yrs Private – Commercial P15 Structural Engineer 16 yrs Public / Government P16 Architect 17 yrs Mixed P17 Quantity Surveyor 15 yrs Public / Government P18 Structural Engineer 17 yrs Mixed P19 Civil Engineer 11 yrs Mixed P20 Architect 14 yrs Public / Government Source: Field data, 2026 Section C: The Influence of Regulatory Policy on Practice Phase 1 anchor: Sustainability provisions in the NBC are discretionary and aspirational; NBC lacks statutory force; KADGIS permit review does not apply sustainability criteria. IC1. Phase 1 analysis found that the NBC 2019’s provisions on sustainable materials, such as encouraging locally sourced or recycled materials, use non-binding language and carry no enforcement mechanism. In your experience, does this reflect the reality of how the NBC is applied on projects in Kaduna? How does the Code’s lack of statutory backing affect how you and your colleagues treat its recommendations? IC2. With respect to the KADGIS permit process, how closely are material specifications actually, examined during plan approval in your experience? Can you describe a specific instance where the regulatory process either supported or failed to support a sustainable material choice? IC3. Phase 1 identified a complete absence of financial incentives for sustainable material use in either the NBC or the KURPL. How significant a barrier is this in your practice, and what form of incentive, if it were available, would most change your specification behaviour? Findings This section produced the study’s bluntest findings. Participants rated regulatory influence very low, responses were almost uniformly critical of both the NBC and the KADGIS permit process. P11 (Structural Engineer, 18 yrs) said: “The NBC is a nice document but it has no teeth. Nobody gets punished for ignoring it. We all know that.” On the permit process, P02 (Civil Engineer, 10yrs) explained: “KADGIS looks at whether your drawings are complete IJEMT and your setbacks are correct. Nobody is checking what brand of block you used or where it came from.” P13 (Civil Engineer, 13 yrs) added: “Once the permit is approved, inspectors rarely show up. A lot of what actually gets built on site is different from what was submitted.” More evidently, no one could identify or recall a regulation that specifically requires the use of a sustainable material. Section D: Factors within Professional Practice that Determine Material Selection Phase 1 anchor: In the absence of mandatory SBM provisions, material selection is governed by non-regulatory factors. Life-cycle/embodied carbon considerations are entirely absent from both instruments. ID1. When regulatory requirements provide little or no direction on material sustainability, what factors most powerfully determine what materials you specify? Can you walk me through a recent project as an example? ID2. Phase 1 found that neither the NBC nor the KURPL contains any provision on life- cycle assessment or embodied carbon. Do these concepts feature in your practice at all? If not, what would need to change, at the regulatory, organisational, or educational level, for them to become routine considerations? ID3. How do you navigate the tension between client budget pressure and the specification? of sustainable materials? Can you describe a situation where this tension arose and how it was resolved? Findings Here, the findings show that when regulation is weak, other forces take over hence cost emerged as the dominant driver, followed by client pressure and supply chain limitations. P03 (Quantity Surveyor, 15 yrs) put it simply: “Cost is king. If a sustainable option costs more upfront, the client says no, and that is the end of the matter.” On the supply side, P09 (Architect, 14 yrs) noted: “I know compressed earth blocks work. I have seen them used. But if you try finding a consistent supplier in Kaduna for a mid-size project, it is a real challenge.” In addition, the response from about 18 respondents show that life-cycle thinking and embodied carbon are virtually absent from daily practice. P05 (Structural Engineer, 11 yrs) confirmed: “Life-cycle cost is something I learned about in school but never practiced. P03 (Quantity Surveyor, 15 yrs) says: I have never done that calculation on an actual project here.” Section E: Professional Body, Continuing Development, and Institutional Support Phase 1 anchor: Neither the NBC nor the KURPL creates linkage between professional registration obligations and sustainable practice. IE1. To what extent does your professional body actively promote sustainable material selection as part of its regulatory or CPD function in Kaduna? Do you believe professional registration should carry explicit obligations regarding environmental practice, and if so, what form should those obligations take? Findings Professional bodies fared poorly. P15 (Structural Engineer, 16 yrs) said: “I am an NSE member. The last time sustainability came up strongly in a meeting was maybe three years ago, and it was briefly. There is no real programme for it.” Yet despite the poor support, majority showed strong support for making CPD on sustainability mandatory, suggesting that professionals recognise the gap even if institutions are not filling it. IJEMT Section F: Recommendations for Policy and Practice Reform Phase 1 anchor: Both instruments lack financial incentives, a national SBM catalogue, and a green building certification pathway. IF1. Based on the regulatory gaps identified in this study, specifically the absence of mandatory SBM requirements, financial incentives, and a national green building framework, what one or two reforms to the regulatory environment would you prioritise, and why? IF2. Looking forward five to ten years, do you see the conditions in Kaduna’s construction industry changing in a way that would make sustainable material selection more routine? What would need to happen for that change to occur? Findings Surprisingly, Section F had the most positive response. P07 (Quantity Surveyor, 10 yrs) said: “If specifying sustainable materials saved the client money on the permit or gave them a tax break, I could sell that idea easily. Right now, it costs more and nobody benefits officially.” P04 (Architect,11 yrs) added: “A simple list - these are the materials that count as sustainable in Nigeria, and these are the ones approved for use in North-West climate, simple! It would change everything. We are guessing right now.” Discussion The combined findings show a consistent picture that Nigeria’s regulatory framework for sustainable building materials exists in name but not in practice. The NBC 2019 contains some language pointing toward sustainability, but that language is soft, unenforceable, and largely unknown to practitioners on the ground. The KURPL 2018 barely mentions materials at all. When regulation is this weak, the market defaults to its most powerful signal which is cost. The result is a construction industry in Kaduna where the choice of building materials is driven almost entirely by upfront price, client preference, and what happens to be available locally, with sustainability rarely entering the conversation. What makes this situation particularly hard to break is that it is self-reinforcing. Weak regulation gives professionals no obligation to use sustainable materials. No obligation means no demand. No demand means suppliers do not develop the supply chain. Scarce supply makes sustainable materials more expensive and harder to find. High cost and low availability give clients more reason to reject them, which gives professionals less incentive to specify them, and so the cycle continues. In relation to the literature, these findings are broadly consistent with the existing literature, but they also add important local detail. For instance, the study agrees with Amuda-Yusuf et al., 2020 assertion that sustainability is not being adequately embedded in Nigerian professional education (Section B). The study goes further to identify this as a Knowledge gap showing that education specifically fails at equipping students to evaluate material sustainability. Unegbu et al. (2025) and Abisuga & Okuntade, 2020 both document an enforcement gap in Nigeria’s building regulatory system, and this study confirms that gap acutely in Kaduna. The consistently low scores on regulatory influence (Section C) go further than most previous studies in quantifying just how little the existing framework is felt in daily practice. The dominance of cost as a barrier (Section D) aligns with Windapo (2013), who identify high upfront cost as the primary obstacle to sustainable material adoption across sub-Saharan Africa. However, this study adds an important distinction, the literature tends to treat cost as a market problem, whereas professionals here point to it as a regulatory problem. It is precisely because there are no incentives, that is, no tax relief, no reduced permit fees, no green procurement targets e.t.c. that cost functions as an absolute barrier rather than one factor among several. The near-zero engagement with life-cycle cost and embodied carbon (Section D) aligns with IJEMT Akinshipe et al. (2019) and Mogaji et al. (2024), who found that sustainability thinking in Nigerian construction remains shallow and largely theoretical. However, the present study traces this more specifically to the regulatory framework, when neither the NBC nor the KURPL requires or even references these concepts, professionals have neither the mandate nor the reference point to apply them. This is in stark contrast with international contexts where LEED, BREEAM, or mandatory carbon reporting obligations push life-cycle thinking into routine practice (Doan et al., 2017). The finding on professional bodies (Section E) adds to what Amuda-Yusuf et al. (2020) describe as the “institutional vacuum” surrounding sustainable construction in Nigeria. The high support for mandatory CPD (Section E) suggests professionals are not resistant to change, they simply lack the institutional structure to enable it. Implications The most urgent policy need is to give the NBC legal force. A voluntary code consulted by a few and ignored by most cannot drive industry-wide change. If the NBC is enacted as an Act of the National Assembly with clear penalties for non-compliance, the entire compliance landscape shifts. Alongside this, both the NBC and the KURPL need explicit, mandatory provisions on sustainable materials, not “encouragements” but requirements, with thresholds that can be verified. The introduction of financial incentives, that is reduced permit fees, tax credits, or preferential access to government contracts for sustainable projects, would be the single most impactful lever available to policymakers, given the cost sensitivity revealed across this data. Finally, the KADGIS permit process needs a sustainability component. Submitted material schedules should be checked against a national list of approved sustainable materials, not just for structural compliance. Firms need internal sustainability policies. Only 2 of 20 participants reported that their organisation had any formal process for evaluating material sustainability. Even simple internal checklists or a designated sustainability lead within a practice would create the organisational conditions for more consistent SBM specification. At the individual level, professionals expressed strong appetite for CPD, and professional bodies should treat this as a mandate. Sustainability should be embedded not just in occasional seminars but in core CPD requirements for annual registration renewal. On the client side, professionals repeatedly identified client demand, or the lack of it, as a powerful gatekeeper. This suggests that awareness campaigns targeting building owners and developers, not just practitioners, are needed to shift market expectations. Conclusion and Recommendations Summary of the Study This study set out to understand how regulatory policy and professional practice together shape the selection of sustainable building materials in Kaduna State, Nigeria. Using an explanatory sequential mixed-methods design, Phase 1 carried out a systematic document analysis of the National Building Code 2019 and the Kaduna State Urban and Regional Planning Law 2018. Phase 2 collected interview data from 20 built environment professionals in Kaduna. The two phases were formally connected: Phase 1 findings were embedded directly into the Phase 2 instruments, so that professionals responded to documented policy realities rather than general questions. Conclusion The central finding of this study is that the regulatory framework governing sustainable building material selection in Nigeria is not yet fit for purpose. Both the NBC and the IJEMT KURPL lack the legal force, specific mandates, enforcement mechanisms, and financial incentives needed to change professional behaviour. In this vacuum, decisions are governed by cost, client pressure, and supply chain availability, and none of which currently favour sustainable materials. Professionals are not hostile to sustainability; many are aware of it and willing to engage with it. But awareness alone does not produce change when the system (regulatory, institutional, and market) provides no support, no obligation, and no reward for sustainable choices. The gap between what policy documents say and what happens on building sites in Kaduna is wide, and it will not close without deliberate, coordinated action from government, professional bodies, and the industry. Nevertheless, this study has a limitation of the geographic scope which is limited to Kaduna urban centre, so the findings may not fully represent conditions in other Nigerian states with different regulatory histories or market conditions. Therefore, future research could explore a larger-scale national survey across multiple states, this would test whether the findings here are specific to Kaduna or reflect a wider pattern. Also, a comparative study between states that have domesticated the NBC and those that have not could reveal what difference formal state adoption makes in practice. Research into the perspectives of building materials manufacturers and suppliers, whose role in the supply chain was outside the scope of this study, would add an important dimension. Finally, a longitudinal study tracking how professional practice evolves if the NBC is eventually enacted as law would provide valuable evidence on the effect of regulatory change on material selection behaviour. Recommendations Based on the findings, the following specific actions are recommended: 1. The Federal Government of Nigeria needs to enact the NBC as primary legislation with mandatory SBM clauses and penalties. This is of high priority and they should in addition create a national pre-approved sustainable materials catalogue for Nigerian climate zones. Tax incentives or reduced permit fees for certified sustainable projects should also be Introduce. 2. Kaduna State Government should consider amending the KURPL 2018 or enact a dedicated state green building policy with explicit SBM requirements. Also, KADGIS needs to add a sustainability checklist to the building permit review process and strengthen post- permit site inspection, specifically for material compliance. 3. Mandatory CPD on sustainable construction as a condition of annual registration renewal should be introduced by the relevant professional bodies (NIA / NSE / NIOB / NIQS). They should endeavour to develop clear practice guidelines defining sustainable materials in the Nigerian context. 4. Adopting internal sustainability policies and simple checklists for material specification should be a part of Construction Firms. They should also consider investing in client education to shift demand toward sustainable alternatives. IJEMT References Abisuga, A. O., & Okuntade, T. F. (2020). The Current State of Green Building Development in Nigerian Construction Industry: Policy and Implications. In Z. Gou (Ed.), Green Building in Developing Countries: Policy, Strategy and Technology (pp. 129–146). Springer International Publishing. https://doi.org/10.1007/978-3-030-24650-1_7 Abisuga, A. O., & Oyekanmi, O. O. (2014). 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