Engineer warns of weak foundations as Eastleigh building collapse raises safety concerns

Weak foundations, substandard construction materials, faulty structural designs, and poor supervision are among the key factors that contribute to building collapses, the immediate past President of the Association of Consulting Engineers of Kenya, Eng. Jane Mutulili has warned.

Eng. Mutulili says building safety depends on proper structural design, quality materials and the correct integration of structural components throughout construction.

Speaking on Radio Generation on Friday, October 30, Mutulili explained that structural weaknesses at any stage of construction can compromise an entire building, potentially resulting in catastrophic failure.

Using the example of a four-legged chair, she illustrated how unstable ground can affect the stability of a structure.

She explained that a chair placed on unstable ground could sink under its own weight, while one leg resting on softer ground could cause it to tilt. The same principle, she said, applies to buildings whose foundations are not adequately designed for the conditions of the construction site.

“The first thing that we do in buildings is foundations. We do what we call geotechnical investigations, and those geotechnical investigations establish whether whatever building you put on that site will actually stand on those foundations. If your foundations are not firm, it doesn't matter what you put there; your building is going to fail,” she said.

Mutulili identified four critical areas where construction failures can occur: structural design, construction materials, workmanship and failure to adhere to approved architectural and engineering drawings.

She explained that engineers must calculate the weight a building is expected to carry, including permanent structural components and additional loads from occupants, furniture and other movable items.

Columns, beams and slabs must work together to distribute the weight safely to the foundations. Any weakness in these components, whether arising from poor design or construction, could compromise the stability of the entire structure.

On construction materials, Mutulili warned that replacing specified materials with inferior alternatives could undermine even a technically sound engineering design.

“If my design was based on being supported by 12-millimetre diameter steel, and you are giving me 10.5 millimetres, you have already compromised it. Even my factor of safety has already been compromised,” she explained.

The Engineer also raised concerns about contractors who disregard engineering specifications by using incorrect concrete mixtures, reducing reinforcement bars or changing the positioning of structural columns.

The engineer further cautioned against adding floors to existing buildings without consulting qualified professionals, noting that safety margins incorporated into an original design should not be treated as permission to increase a building's height.

“You cannot construct just because your neighbour has constructed a four- or five-storey building and decide that you also want to do the same. The dynamics between your plot of land and your neighbour's plot are different,” she added.

Her warning comes a week after an 18-storey building under construction collapsed along 9th Street in Eastleigh on October 23, triggering a major rescue operation and renewed scrutiny of construction safety in Nairobi.

By Friday, October 30, six people had been rescued from the rubble, while the body of a woman was recovered at about 6.30 am and taken to Nairobi City Mortuary for DNA testing and identification. Sixteen people remained unaccounted for as emergency teams continued searching the site.

The incident has also raised questions about construction approvals and regulatory oversight, particularly after Nairobi Governor Johnson Sakaja said the development lacked the necessary building approval.

The National Environment Management Authority (NEMA) separately said it had not issued an environmental impact assessment licence for the project.

The Director of Public Prosecutions has since directed the Directorate of Criminal Investigations to investigate the roles of county officials, developers, contractors and construction professionals involved in the project.

The Eastleigh collapse adds to a history of deadly building failures in Kenya, including the 1996 Sunbeam building tragedy in Nairobi, which killed 16 people when a canopy and part of a wall collapsed on commuters sheltering from rain.

In April 2016, a building in Huruma collapsed, killing 51 people and injuring about 140 others. Three years later, the collapse of classrooms at Precious Talent Top School in Nairobi killed seven pupils and injured more than 50.

A compilation by Stats Kenya recorded at least 83 building collapses, 88 deaths and 131 injuries across the country between January 2020 and October 24, 2026.

The Architectural Association of Kenya's 2024 Status of the Built Environment report also highlighted concerns about building safety. Of 1,333 buildings inspected during the 2023/24 financial year, 570 were classified as safe, 246 as unsafe and 42 as dangerous.

Mutulili said preventing further tragedies requires strict adherence to engineering standards, competent professionals, quality construction materials and effective supervision at every stage of development.

She stressed that building safety must be prioritised from the initial geotechnical investigations and foundation design through to the completion of construction, rather than addressed only after structural problems emerge.