Inside the construction process and why some buildings collapse

 

Search and rescue efforts at the site of a collapsed building in Karen, Nairobi, on January 10, 2026. [Boniface Okendo, Standard]

Every building begins with an idea, but not every structure stands the test of time.

From surveying the land to laying the foundations, from designing floors to installing lifts, a chain of decisions determines whether a building rises safely or collapses.

In recent months, the country has witnessed houses collapsing, sinking, being demolished or flagged as high-risk structures. The latest case, a 16-storey building that collapsed in South C, has raised fresh questions about how buildings are constructed and who is accountable when things go wrong.

So, where does the process begin, and where do the cracks appear?According to architect Martin Muyonga, the process starts when a client approaches an architect with an idea for a proposed development. Before any design work begins, the client is referred to a surveyor to assess the land.

Survey expert Eric Ngomo explains that the surveyor’s first responsibility is to confirm land ownership. “First and foremost, we must confirm that the land the client is presenting actually belongs to them,” he says.

Topographic mapping

Once ownership is verified, the surveyor measures the land’s physical features and prepares a topographic map. “The map shows the size of the land, surrounding physical features and available services, such as sewer lines,” Ngomo explains.

Armed with this information, the client is referred back to the architect and structural engineer, who work together to design the building.

Muyonga says the architect begins with a sketch that captures the client’s ideas, before developing a scheme drawing that can be submitted to relevant authorities for approval. “The scheme drawing shows what the building will look like,” he says.

At this stage, the architect shares the drawings with the structural engineer, and the two professionals refine the design together to ensure it meets the client’s needs while remaining structurally sound. The final structural drawings are then submitted for approval.

Once approvals are granted, the drawings, now referred to as working drawings, are sent back to the surveyor for setting out.

“Setting out means placing what has been designed onto the ground, positioning the building exactly where it should be,” Ngomo explains.

This process involves transferring designs from paper to the site, marking precise locations for foundations, walls and other structural elements using accurate measurements and control points. At this stage, the site is ready for construction to begin.

Required approvals

By law, developers must first confirm clear land ownership and obtain a survey plan from a licensed surveyor. Architectural and structural drawings must be prepared by registered professionals in line with the National Building Code.

These drawings are submitted to the county government for approval under physical and land-use planning regulations. Medium- and large-scale projects must also secure an Environmental Impact Assessment licence from the National Environment Management Authority (NEMA) and be registered with the National Construction Authority (NCA) before works begin.

Engineer Eric Njoroge says construction can only start once all statutory approvals are in place and a registered contractor has been selected.

Construction begins with excavation and foundation works, guided by approved drawings. The structural engineer inspects critical stages, such as reinforcement placement and concrete casting. Engineers continue inspecting columns, beams and slabs to ensure specifications are met. Architects ensure the building conforms to designs, while surveyors monitor alignment and verticality.

For multi-storey buildings, concrete tests are conducted regularly, and deviations from approved designs must be corrected. Finishing works, including plumbing, electrical installations, lifts and external works, are carried out in line with safety standards.

When a building begins to crack or collapses, whether complete or near completion, investigations are immediately launched.

“When cracks appear, work must stop. A stop-work order is issued and we audit both the design and construction,” says Njoroge. “We check whether the structural design was implemented correctly, whether the right materials were used and whether quality control procedures were followed.”

Survey 0versight

Ngomo adds that survey records are also examined. “Surveyors monitor verticality and positioning from the ground up,” he says. “If a building deviates from its intended layout or columns are misaligned, structural integrity can be compromised.”

Muyonga notes that faults may also arise when developers or contractors ignore specifications or use substandard materials and workmanship.

The experts agree that responsibility is often shared. Fault may lie with the structural engineer if foundations were poorly designed or soil conditions ignored, with the contractor if approved layouts were altered, or with the client or developer if buildings exceeded approved designs.

Ultimately, they emphasise that building safety depends on proper planning, strict adherence to approvals, professional oversight and compliance with standards at every stage, from idea to completion.