What Caused the Surfside Building Collapse, and Who Could Have Averted It?

A group of people in hardhats stands amid the rubble of the collapsed building.
Search-and-rescue teams look for possible survivors and to recover remains on Monday, four days after the collapse of the Champlain Towers South. Joe Raedle/Getty Images

The 12-story condo tower that collapsed north of Miami Beach last week may prove to be the deadliest building accident in U.S. history. As of Tuesday morning, 11 residents are dead and 150 are missing.

As the search through the rubble goes on, officials and journalists are trying to piece together what went wrong. It’s a matter of public interest, but it’s also a more urgent concern for neighbors in the high-rise buildings along South Florida’s barrier islands, where every crack in the wall has taken on a new and ominous significance.


Why did Champlain Towers South collapse? And who might share in the blame? Even a full investigation may not yield one answer, but events of the past few years offer some clues. Here are some possibilities.

The Potential Causes

The pool slab: In 2018, an inspection report prepared by engineer Frank Morabito noted a “major error” in the building’s design: The slab between the pool and the parking garage was flat, not sloped, causing water to puddle and corrode the concrete below. “The failed waterproofing is causing major structural damage. … [F]ailure to replace the waterproofing in the near future will cause the extent of the concrete deterioration to expand exponentially.”


According to the Miami Herald, a pool contractor who surveyed the building days before the collapse photographed seriously degraded concrete in the pool equipment room, and a deep puddle of standing water in a parking spot beneath the pool.


That would track with the testimony of Champlain Towers South unit owner Michael Stratton, who said his wife, Cassie, (now missing) told him on the phone on Thursday morning that she could see, from their fourth-floor unit, a hole near the pool. Then the line went dead.

Damage from rain, ocean water, and salty air: The local CBS affiliate tracked down a retired maintenance manager from the property who said ocean water routinely pooled in the garage and pumps “never could keep up with it.”

Morabito’s report also documented substantial damage to concrete above ground, such as balconies. Some concrete interacts well with water (like jetties), but reinforced concrete is threaded through with rebar. This internal steel web gives concrete new structural powers, but those powers go away when the rebar gets wet, rusts, and weakens. (Corroded steel hidden inside concrete was also a problem with the Morandi Bridge, which collapsed in Genoa, Italy, in 2018.)


But salty air and saltwater are common features to every American coastline, and there’s no apparent reason why Champlain Towers South would have weathered them worse than any other building.


Problems underground: Another suggestion is that water was the cause of the collapse in a slightly less direct way, by affecting the integrity of the earth beneath the building.

USA Today tracked down research, originally published by Italian researcher Simone Fiaschi, that demonstrated that the building was sinking into the ground as long ago as the 1990s, albeit at the slow rate of 2 millimeters per year. Sinkholes are also common in South Florida, though they’re rare on the barrier island.

Donna DiMaggio Berger, a lawyer who represents the Champlain condo association, told the Washington Post that a “subsurface, structural issue” likely caused the collapse. “This building was on pilings buffeted by the Atlantic Ocean and the Intracoastal Waterway,” she said. “We’ve got water coming at this thing from both sides.”

The Possible Players

William M. Friedman & Associates Architects Inc. and Breiterman Jurado & Associates, Consulting Engineers: That’s the team responsible for the building’s design, 40 years ago. The flat pool slab was their idea. Those were the boom years in Miami, and shoddy construction practices abounded.


Morabito Consultants: Did Frank Morabito grasp, and accurately convey, the extent of the damage at Champlain Towers South? Though his October 2018 report warned the board to deal with “major structural damage” in the “near future,” it did not suggest the building might be at risk of collapse. Berger, the condo lawyer, suggested to the New York Times that the condo board’s failure to address the pool deck before the middle of 2021 can be read as a response to that assessment. “All boards can do is rely on the advice of the professional advisers that they engaged,” she said.


On Saturday, Morabito released a statement saying that, “Among other things, our report detailed significant cracks and breaks in the concrete, which required repairs to ensure the safety of the residents and the public.”


Surfside, Florida: Condo board member Mara Chouela forwarded Morabito’s report to a Surfside building official, Ross Prieto, who made a guest appearance at the condo board meeting the following month and announced that based on the report it “appeared the building is in very good shape,” according to the meeting notes. (Prieto told the New York Post he does not recall reviewing the report.)

The Champlain Towers South Condominium Association: Even if it didn’t warn of imminent collapse, Morabito’s report was alarming. Why did it take the condo board more than 18 months to engage Morabito again for a “40-year Building Repair and Restoration Plan”? Might it have had something to do with the fact that the repairs required an investment of $15 million divided between the association’s 136 units—more than $100,000 in maintenance, per unit, in a building where apartments have recently sold in the mid-six figures? As recently as April, two-and-a-half years after Morabito’s report, the condo board president was still trying to sell owners on the high-priced repairs. Two residents have filed suit against the condo association in the wake of the collapse.


A neighboring building: Maybe Morabito was right to strike a moderate tone, and the board was right to delay, because conditions deteriorated rapidly after the inspection. At a press conference last week, Surfside Town Commissioner Eliana Salzhauer said that Champlain Towers residents complained about vibrations and cracks related to a much larger building under construction this year. “Some of those things may have been factors,” she said.

Miami-Dade County: To obtain Miami-Dade’s recertification for multiunit, 40-year-old buildings, owners must hire a licensed architect or engineer to assess its structural integrity, electrical system, emergency lighting, and other key features. Engineers are supposed to follow professional codes of conduct, but there’s plenty of gray area between negligence and demanding tens of millions in repairs. Elsewhere, engineers hired to see owners through county regulations have sometimes simply told owners what they want to hear, and it’s not hard to see why: Buildings rarely fall down and no owner is going to want to hire an inspector with a reputation for nitpicking. Does Miami-Dade’s system have a fundamental flaw, in that its engineers are hired and paid by the very buildings they are supposed to be assessing on behalf of the public?

Climate change: To the extent flooding in the garage or soil movement underground is linked to Miami’s King Tides, heavy rainfall, or rising water table, it would be possibly to connect the structural damage to the changing climate. That was the view of Salzhauer, the Surfside commissioner, who had a grim message for the town on Thursday morning: “I think this is all tied to sea-level rise and our overdevelopment. And Mother Earth comes back, and the ocean comes back, and takes it.”