Surfside weighs tighter monitoring of new construction in wake of sinking buildings study

Miami Herald

31-01-2025

Surfside is discussing tightening regulations and fixing 'flaws and loopholes' to better protect buildings from potential damage from nearby construction, in response to a study that found that 35 Miami buildings along Miami's barrier islands were sinking beyond what would be expected.
While heavy buildings are expected to sink a few inches during and after construction as they naturally compress the layers of soil underneath, the University of Miami study showed that for some buildings, that process continued beyond what was typically expected. Nearby construction, the study found, 'accelerated, if not instigated,' the sinking of some of the 35 buildings identified in the study, which included the Porsche Design Tower, the Surf Club Towers, Faena Hotel, Trump Tower III and Trump International Beach Resorts.
Though there are no immediate safety concerns, the study highlights the need to better understand why buildings that accommodate tens of thousands of residents and tourists are sinking, and points to a 'definite need to have more oversight and accountability for new construction projects,' Surfside's Vice Mayor, Tina Paul, told the Herald earlier this month.
In a commission meeting Wednesday evening, Paul proposed strengthening regulations for new construction projects as 'there's a lot of flaws, a lot of loopholes there, because they (developers) just go through the motions.'
High-rises typically stand on pilings that are often sunk 100 to 200 feet into the ground, causing vibration that could cause damage to nearby buildings. Currently, developers are required to assess and monitor any potential damage within a 300-feet radius, but that, Paul said, 'doesn't quite encompass the area that's being affected, according to the study, so it should extend to other properties.'
Paul also proposed that monitoring should be carried out by independent, third-party companies, not companies contracted by the developer as developers 'are not really looking to protect your (the neighboring) property.'
In an interview after the commission meeting, John Pistorino, who sits on the state's engineering board and has worked as an engineer in Miami for more than five decades, said land surveyors generally only monitored how much the development itself was sinking – a process known in construction as settlement – and that it'd be 'good for everyone's interest' to extend settlement monitoring to nearby buildings during and until a year after construction.
New construction techniques, however, cause less vibration than in the past, Pistorino said, and extending the monitoring radius might not be necessary.
Other commission members agreed with Paul, saying they had felt vibration in their own homes even when the construction drilling was way beyond 300 feet away. They also pointed to the 2021 collapse of Champlain Tower South, which killed 98 people, as a reason for heightened scrutiny.
A 2020 study by Florida International University concluded that sinking land surrounding the Champlain Towers couldn't have caused the collapse, while an investigation by the Herald found that flaws in the construction and design as well as a lack of proper maintenance likely caused the tragedy. A final federal report on the cause is expected in the spring of 2026.
Still, the new study resurfaced fears and concerns by residents.
'After having gone through the tragedy of Champlain Tower South, our town has a special responsibility to address problems like this with open eyes and to make sure that nothing like this – what happened here – happens anywhere again,' Commissioner Gerardo Vildostegui said in Wednesday's commission hearing.
The study used more than 200 satellite images, taken between 2016 and 2023, and found that some buildings had subsided between 0.8 and 3 inches. Issues can occur if different parts of a building sink at different rates, a process known as differential subsidence. Though the UM study did not seek to evaluate whether this type of differential subsidence took place, engineers have said that the greater the subsidence itself, the greater the risk that it is also uneven.
As the Fendi Chateau and Surf Club North, both named in the study, are among the widest buildings in Surfside, Vildostegui wondered whether wider buildings are at higher risk of differential subsidence. 'That's when you can have some kind of danger,' Vildostegui said. 'So it might be something for our commission to consider whether we want to put in a maximum building width,' he said.
As other reasons are likely contributing to the sinking, the study's authors have repeatedly highlighted the need for more research to fully understand what's happening underneath our feet. That some of the subsidence continued at a constant rate was 'puzzling', according to the study, which points to tidal flows and stormwater injection as 'candidates to explain the constant rate component.'
Greenhouse gas emissions are driving temperature increases that make rain showers more intense, and high-rises have typically added stormwater injection wells to alleviate flooding. Fresh water, the study explains, could shift and rearrange lawyers of sand, and even 'lead to the dissolution of the limestone,' that South Florida is built on.
Paul, who attended a seminar with one of the authors, said that 'it's possible that the storm water and tidal flows are affecting the limestone, and this is something that needs to be studied.'
Some members of the commission, however, feared litigation after Town Manager Mark Blumstein said that some of the properties identified in the study 'have their own experts preparing a response. This may also lead to litigation,' he said. Though it was not clear what kind of litigation would result from a scientific, peer-reviewed study, 'obviously, that impacts their bottom line.'
Motions to ask the state, county and relevant government agencies to take note of the study and to create a database of soil conditions assessed before construction did not have the immediate, full support of the commission. Instead, commissioners agreed to hold a workshop with one of the study's authors next month to learn more about the steps they could take.
Mayor Charles Burkett cautioned that sinking of land and buildings was an issue Surfside alone could not solve. 'The reality is, little Surfside is not going to change the direction of this very important, big issue,' he said. 'The state and the county need to be urging us to be aware of things, and they need to write the laws. They need to change the laws.'
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