South Florida High-Rises Are Settling: Experts Urge Mandatory Sensors And Centralized Monitoring

Overview

In June 2024 the 28‑story Marenas condominium hotel in Sunny Isles Beach installed sensors to track whether foundation work next door for the new St. Regis Residences could affect its building. The St. Regis development, planned as twin towers rising roughly 750 feet and supported by pilings driven about 200 feet into the ground, will be the tallest structure in the city when completed.

What Happened

Shortly after foundation work began, a sensor at the Marenas registered vibrations that alarmed the condominium board and prompted a temporary pause in nearby construction. Lisa Gardener, president of the Marenas condo association, said the response reflects an urgent need to watch even small movements to protect residents and property. Developers Fortune International Group and Chateau Group confirmed the project is progressing steadily but declined interviews and did not answer written questions; units start at about $4.5 million.

“It just happens, it’s going to happen. Now we have to stay on top of it, no matter how small,” said Lisa Gardener.

Wider Pattern: Unexpected Settlement

Experts increasingly suspect adjacent construction is a leading cause of unexplained sinking in some luxury high‑rises along Sunny Isles Beach, a roughly 2.5‑mile oceanfront corridor. A 2024 scientific study found more than 70 percent of the dense cluster of towers built in the past 25 years showed evidence of settlement beyond expectations.

A Miami Herald investigation analyzed more than 40 geotechnical reports (over 2,000 pages) filed with local building departments and interviewed a dozen experts. The reporting found that many projects had considered not only their own predicted settlement but also the potential for construction to accelerate sinking in neighboring buildings. One recent geotechnical report for the Bentley Residences warns that construction could cause settlement at the adjacent Turnberry Ocean Club — estimating roughly three inches of sinking — and advises project owners to prepare to address any impacts.

Why Monitoring Matters

Historically, engineers calculate settlement before construction and monitor it during active work. Long‑term, post‑construction monitoring is uncommon. Developers are currently liable for structural defects tied to construction — including unexpected settlement — for seven years, a reduction from ten years after lobbying in 2023. Experts worry that without longer monitoring windows and independent analysis, patterns of delayed settlement will go undetected until damage occurs.

Expert Recommendations

• Mandate Foundation Sensors: Install sensors during construction to detect subtle movements invisible to residents but that may presage structural harm. Agencies such as the Florida Department of Transportation already use sensors on public infrastructure.
• Centralize And Open Data: Compile geotechnical reports and monitoring results in an accessible repository so independent experts can analyze trends that are currently dispersed across agencies and files.
• Fund Long-Term Monitoring And Research: Create a research program to understand rates and timelines of settlement and the effects of adjacent construction.

“We need more monitoring and more subsurface exploration, some sort of research program, to at least know that settlements are happening and at what rate, and what is the timeframe of their occurrence,” said Anil Misra, chair of civil and environmental engineering at Florida International University.

Obstacles And Industry Resistance

Engineers and vendors report developer resistance to continuous monitoring. Jean‑Pierre Bardet, former dean of the University of Miami School of Engineering, noted that owners fear unfavorable data could depress property values, increase insurance costs, or be used in litigation. Kumar Allady, who founded a company whose sensors are used by FDOT, recalled developers threatening to cut cables when monitoring was proposed for private projects. For many developers, sensors are an added cost that could produce evidence used against them; experts say mandates or incentives may be required.

Economic Stakes

Experts stress that the region has strong incentives to act: Miami‑Dade’s development and real‑estate industries represent roughly $50 billion annually — about one quarter of the county’s GDP. Investing in monitoring and transparent data would both protect residents and help stabilize a critical economic sector.

Reporting And Next Steps

The Herald reviewed more than 40 geotechnical reports covering nearly the entire Sunny Isles oceanfront, spoke with geotechnical engineers and geologists, and cross‑referenced data and interviews for this investigation. Local officials, including Sunny Isles Beach Mayor Larisa Svechin, did not respond to requests about whether they would support expanded monitoring.

If implemented, the experts say the region could lead advances in foundation engineering and monitoring that would serve as a model for other coastal cities facing similar risks.

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Credits: Denise Hruby | Climate Reporter; Susan Merriam | Data/Visual Journalist; Amy Reyes | Editor; Matias J. Ocner | Visual Journalist; Carl Juste | Visual Journalist.

For questions, contact the climate team at climate@miamiherald.com.