The 21 storey collapsed Ikoyi building was initially designed for 12 floors, sources told The Nigerian Xpress.
According to the source, who is familiar with the matter, the owner told the developers to increase the floors to 21 to make more money, the source said.
This led to the structural consultants pulling out last year when the client insisted on adding additional 15 floors.
According to multiple eyewitnesses, the owner was inside the building when it collapsed on Monday afternoon.