CHAPTER ONE

INTRODUCTION

1.1 Background of the Study

Structural collapse is a global problem, yet its human and economic toll is heaviest in developing countries. In Nigeria, the frequency and scale of building failures have turned what was once an occasional tragedy into a regular feature of national news, and the losses in lives and property have become a source of serious public and professional concern. Awoyera et al. (2021) describe the persistence of collapses over several decades as a growing worry for investors and government alike. The problem is not unique to Nigeria: Ayinla et al. (2024) place Nigerian cases alongside well-known failures elsewhere, such as the Sampoong Department Store in South Korea (1995) and the Champlain Towers South in Florida (2021).

A building fails when its components can no longer perform the functions expected of them. It collapses when part or all of the structure gives way so that the building can no longer serve its intended purpose. Failure can emerge during construction as well as after a building has been occupied. Recent Nigerian studies attribute documented collapses to defective or substandard materials, limited technical knowledge, disregard for building codes and standards, the engagement of non-professionals, and corruption within the construction industry (Awoyera et al., 2021). The quality of construction materials has also been singled out repeatedly as a contributing factor (Bamigboye et al., 2019), and Ezema and Olatunji (2018) connect collapses in Lagos to weak quality control in the selection, batching and placement of concrete.

The available records show how widespread the problem is. Odeyemi et al. (2019) reviewed collapses between 2009 and 2019 and found structural defects to be the leading cause, with 2014 recording the highest number of incidents and 2016 the highest number of deaths. The South West zone accounted for 34 collapses (60.71% of the total) and 132 deaths (64.08%) over the period. Opawole et al. (2022) report that 64 buildings collapsed between 1974 and 2011 and that Lagos State has recorded more failures than any other part of the federation. Collapses also cut across building types and sizes: the Lagos cases summarised by the same authors include a guesthouse at Ikotun-Egbe in 2014 and a three-storey building that housed a school at Ita-Faaji. They further observe that most collapsed buildings are residential and were procured through unregulated channels.

Outcomes in construction depend heavily on the competence of the people who design, supervise and build. That competence delivers value only where clients and contractors are willing to engage qualified personnel and pay for quality. Opawole et al. (2022) identify the use of uncertified supervisors, weak site quality control and departure from specified concrete mixes among the most significant site-level factors affecting compliance with standards. They also note that many private clients and contractors do not engage professionals at all, and that substitutions such as using thinner reinforcement bars than specified are common among unqualified operators.

The regulatory environment is the second part of the picture. The National Building Code is intended to serve as the master reference for national standards on building design and construction (Opawole et al., 2022). Rules of this kind only protect the public when they are enforced. Opawole et al. (2022) rank an inefficient regulatory framework and weak enforcement among the main procurement-related obstacles to compliance, while Ayinla et al. (2024) report violations of building laws at several levels and stages of construction. In Lagos State, Rotimi et al. (2026) found that compliance with pre-construction documentation varies widely: technical documents such as architectural drawings and structural designs were submitted more consistently than legal documents (for example, land titles) and regulatory documents (for example, environmental impact assessments). They link this unevenness to weak institutional oversight and to a culture of informal construction activity.

1.2 Statement of the Problem

The informal sector in construction can be understood as the segment of firms, workers and clients who build without following the formal procedures of design, planning, permitting and professional supervision. Opawole et al. (2022) describe the Nigerian building industry as dominated by informal activities that frequently depart from laid-down procedures and cannot be fully monitored, with the result that quality breaches and structural failures are common. Rotimi et al. (2026) similarly point to the persistence of informal construction culture as a barrier to regulatory compliance in Lagos.

Buildings deteriorate with age, and it may be impossible to prevent every failure. It is nevertheless necessary to reduce the rate of collapse and the losses that follow. Recent studies address materials (Bamigboye et al., 2019; Opawole et al., 2022), historical incidence and causes (Awoyera et al., 2021; Odeyemi et al., 2019), and regulatory compliance (Rotimi et al., 2026). The informal sector, however, tends to appear in this literature as background context rather than as the main subject of investigation. This study therefore examines the likely causes of building failure and collapse in Nigeria and assesses the contribution of the informal sector, with particular reference to Lagos State.

1.3 Research Objectives

The main objective of the study is to evaluate building failure and collapse in Nigeria in light of the influence of the informal sector. The specific objectives are to:

1. identify the likely causes of building failure and collapse in Nigeria;
2. investigate the contribution of the informal sector to the incidence of building failure and collapse; and
3. propose measures for reducing building failure and collapse in Nigeria, taking account of the role of the informal sector.

1.4 Research Questions

The following research questions were derived from the objectives:

1. What are the likely causes of building failure and collapse in Nigeria?
2. What role does the informal sector play in the incidence of building failure and collapse?
3. What measures can reduce building failure and collapse in Nigeria, given the influence of the informal sector?

1.5 Significance of the Study

The findings should be useful to the general public, building clients, the construction industry, technical educators, and local, state and federal governments. Residents of Lagos State stand to gain in particular. Once the structural factors and the influence of the informal sector have been clearly identified, consistent and impartial application of the recommendations can reduce the incidence of failure.

For the public, the study supports the safety of building owners and occupants by showing the value of constructing to approved specifications. Buildings that are properly designed and built offer safer shelter, lower exposure to hazards, and walls and floors that resist fire and moisture. Draftsmen and technicians will see the need for continuous training so that their skills keep pace with changing technology.

For architects, engineers and builders, the study highlights the range of forces that act on buildings and the importance of working with trained, certified practitioners rather than informal operators. It reinforces the point that the load-bearing capacity of each structural element must be considered, because loads influence design, siting, choice of materials and methods, and the way a building is maintained and used.

For regulators and professional bodies, including the Lagos State physical planning and building control authorities and the Nigerian Institute of Building, the study clarifies how far substandard materials and informal practices contribute to failure. This can support better standards, stronger enforcement and a lower risk of collapse in Lagos State and surrounding areas.

1.6 Delimitation of the Study

Geographically, the study is limited to Lagos State, Nigeria. In scope, it concerns building failure and collapse as influenced by the informal sector, including limited professional training and incompetence. It considers failures of foundations, walls, floors, columns and beams, and roofs.

REFERENCES

Awoyera, P. O., Alfa, J., Odetoyan, A., & Akinwumi, I. I. (2021). Building collapse in Nigeria during recent years – Causes, effects and way forward. IOP Conference Series: Materials Science and Engineering, 1036(1), 012021. https://doi.org/10.1088/1757-899X/1036/1/012021

Ayinla, M. H., et al. (2024, June). Building collapse: Tackling the construction quality gap in Nigeria [Paper presentation]. 2024 ASEE Annual Conference & Exposition, Portland, OR, United States. https://strategy.asee.org/48425

Bamigboye, G. O., Michaels, T., Ede, A. N., Ngene, B. U., Nwanko, C., & Davies, I. (2019). The role of construction materials in building collapse in Nigeria: A review. Journal of Physics: Conference Series, 1378(4), 042022.

Ezema, I. C., & Olatunji, O. (2018). Building collapse in Lagos State, Nigeria: Towards quality control in materials, batching and placement of concrete. Covenant Journal of Research in the Built Environment, 6(1), 25–39.

Odeyemi, S. O., Giwa, Z. T., & Abdulwahab, R. (2019). Building collapse in Nigeria (2009–2019), causes and remedies – A review. Kwara State University institutional repository. https://kwasuspace.kwasu.edu.ng/handle/123456789/3872

Opawole, A., Alao, O. O., Yusuf, A. O., Adu, E. T., & Ofoetan, M. A. (2022). Evaluation of compliance of concreting materials to standards in building projects in Lagos State, Nigeria. Journal of Construction Business and Management, 5(2), 1–19. https://doi.org/10.15641/jcbm.5.2.1182

Rotimi, E. M., Achi, F. O., Oseyomon, I. E., & Agoha, C. D. (2026). Assessment of compliance with pre-construction documentation in Lagos State. Lagos Journal of Environmental Studies, 14(1). https://ljes.unilag.edu.ng/article/view/3109