Search and rescue workers are working in the rubble of the 12-story condominium tower that fell to the ground in a partial building collapse on June 24, 2021 in Surfside, Florida.

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Almost three years before a Florida condominium tower collapsed, an engineer warned that the building’s failure to seal the pool deck was causing “major structural damage.” according to files.

Champlain Towers South, the twelve-story residential tower in Surfside, Florida, partially collapsed in the middle of the night on Thursday. The death toll has risen to four, while 159 are missing.

Officials said at a press conference Saturday that fire and smoke from deep within the remains of the tower are slowing the search. While the rescue effort continues, the City of Surfside has released a number of documents about the building.

Documents released by Surfside authorities late Friday include a 2018 field survey report by Morabito Consultants that found the concrete structural slab under the building’s pool needed repair.

“If the waterproofing is not replaced in the near future, the extent of concrete deterioration will expand exponentially,” the report said.

A view of the grounds during a rescue operation of a 12-story Champlain tower that partially collapsed on June 25, 2021 in Surfside, Florida, USA.

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The company recommended replacing the damaged plates. She also found “frequent cracks and flaking” in the concrete supports, beams and walls of the parking garage. The tower was built in 1981.

The report did not warn of impending danger and it is still unknown what caused the building to collapse. Surfside Mayor Charles Burkett told CNN that he had not seen the 2018 structural field survey report but said it was “not clear at the moment exactly what was going on in this building”. According to the New York Times, the report helped develop plans for a multi-million dollar repair project that should begin soon.

Burkett said during a press conference that he was working on a plan to relocate residents of Champlain Towers North, which was built that same year. FEMA has agreed to pay for the accommodation. City officials are still collecting more information about the Champlain Towers East, which was built in a different style and likely built at a different time.

CNBC asked Morabito Consultants for a comment.