The woman, who was rushed to the nearest hospital, brought the number of survivors to three, while at least eight bodies have been dug out in the past 24 hours.
The building collapsed on Monday morning, when the majority of residents had already left for work. Rescuers said that the death toll was likely to rise significantly, as over 30 people are believed to be missing.
The seven-story residential building was built some 25 years ago without planning permission. Later, the building's owner secured a permit, but illegally added a further five floors to the apartment block. Recently, the building was declared to be unsafe and scheduled for demolition.
The city's Mayor Adel Labib said that the building's owner had recently started illegally reconstructing the ground floor, ignoring repeated orders to cease.
Safety violations have been the cause of numerous building collapses all over Egypt. In November 2006, seven people died under the rubble of a collapsed four-story building in the city of Mansura in northern Egypt. A year earlier, the illegal addition of three floors to a residential building in Alexandria left 19 dead.
