Urban development expert Alfred Omenya warned that weak enforcement of construction regulations, unqualified site supervisors and the use of cheap labour were putting lives at risk as building collapses continued to raise concerns in Nairobi.
Speaking on Radio Generation on Wednesday, Omenya said Kenya had regulations governing construction, but authorities failed to ensure they were followed, allowing buildings to be erected without adequate professional supervision.
“We do have regulations, we don't follow them. We do have provisions of how to probe buildings, how much your buildings are technical. We don't follow them,” he said.
He argued that construction sites often lacked qualified supervisors, with some workers being entrusted with responsibilities despite having no formal training or recognised credentials.
Omenya also blamed the preference for cheap labour, saying contractors sometimes chose workers who charged less without considering the impact on construction quality.
He warned that poor concrete mixing, excessive water and incorrect reinforcement could compromise a building’s strength, even where the original structural design met safety standards.
“Most of these guys don't understand the logic behind the mix of concrete,” he said, explaining that the proportions of cement, sand, ballast and water had to be carefully controlled.
He added that excessive water weakened concrete, while poorly connected or inadequately overlapping steel reinforcement could undermine the strength of beams, columns and slabs.
“You may have the structural design just okay, but then because of that workmanship, the building you're producing is 50 per cent weaker than a building where it has actually been done correctly,” Omenya said.
The expert said qualified structural engineers and trained clerks of works should supervise critical stages of construction, including foundations, beams and slabs, to ensure work met approved designs.
He said the National Construction Authority (NCA) and county governments needed to strengthen inspections to establish whether contractors employed qualified personnel and whether construction followed approved plans.
Omenya said inspections should go beyond checking permits and workers’ protective equipment to assess the actual quality of construction.
He also urged developers to engage professionals even when working with limited budgets, noting that engineers could advise on critical construction stages without necessarily remaining on site every day.
His remarks came amid growing concern over recurring building collapses in Nairobi, following the collapse of a 12-storey building under construction along 9th Street in Eastleigh on October 23, 2026.
The incident triggered a multi-agency search-and-rescue operation, with several people feared trapped beneath the rubble.
The Kenya Red Cross had recorded 52 people as missing, but 32 were subsequently traced and reunited with their families, leaving 20 still unaccounted for.
Authorities cautioned that the outstanding cases did not necessarily mean all 20 people were trapped inside the collapsed building, as investigations into the incident continued.
A Nairobi County report also revealed that 256 cases involving illegal construction were at advanced stages of investigation, highlighting ongoing enforcement challenges in the city.
Kasarani recorded the highest number of cases at 46, followed by Embakasi West with 27 and Embakasi East with 21. Lang’ata had 18 cases, Roysambu and Starehe recorded 16 each, while Mathare had 15, among other areas.
Of the 256 cases, 25 had been processed, with files forwarded to the Office of the Director of Public Prosecutions (ODPP) for review, advice and further action.