A part of the building in the Janga suburb of Pernambuco's capital, Recife, collapsed on Friday morning, local media said. Previous reports put the death toll at 11.
A total of 13 people were found dead at the scene, and one person died in hospital, the Folha de Sao Paolo newspaper reported, adding that there is no information about other missing people.
Two teenagers and a 65-year-old woman were pulled from the rubble alive and rushed to hospital, the report said. Around 50 rescuers and volunteers were involved in search and rescue efforts.
Officials said that the cause of the collapse, which came during heavy rainfalls, remains unknown.