SURFSIDE, Fla. (NewsNation Now) — The ground-floor pool deck of the oceanfront condominium building that collapsed near Miami was resting on a concrete slab that had “major structural damage” and needed to be extensively repaired, according to a 2018 engineering report that also uncovered “abundant cracking and spalling” of concrete columns, beams and walls in the parking garage.

The report was among a series of documents released by the city of Surfside as rescuers continued to dig Saturday through rubble in an effort to find any of the 130 people who remain unaccounted for after the collapse. At least five people were killed.

The report said the waterproofing under the pool deck had failed and had been improperly laid flat instead of sloped, preventing water from draining off.

The firm recommended that the damaged slabs be replaced in what would be a major repair.

These were all problems that should have been dealt with quickly, said Gregg Schlesinger, an attorney specializing in construction defects and a former construction project engineer.

“More exploratory work should’ve been conducted; destructive testing, in and around the areas, to see to what extent those clear signs of structural defect had heard,” Schlesinger said. “That wasn’t done and they had waited three years and still had not performed adequate investigation to determine how bad those defects affected the structural integrity of the entire building.”

Schlesinger told NewsNation the failure to investigate additionally has led to this catastrophe that could’ve been avoided.

“It’s simple. This is a structural element that’s made out of concrete and steel clearly, through this falling, the steel had deteriorated to such a level that the concrete was falling off of columns, off of slab sides, and it was indicative of a serious structural defect in the building,” Schlesinger said.

Watch the full interview in the player above.

The Associated Press contributed to this report.