Authored by Craig M. Dudas, RS, Senior Practice Leader, Construction Advisory.
Published May 21, 2026.
Case Study Overview
A combined Phase I & II Milestone Inspection across two 18-story oceanfront towers uncovered significant structural deterioration, prompted immediate safety action, and gave the association the documentation needed to protect residents and plan remediation.
|
SERVICE LINES |
SECTOR |
LOCATION |
ENGAGEMENT LEAD |
|---|---|---|---|
|
Phase I & II Milestone Inspections |
High-Rise Condominium |
Marco Island, Florida |
Rimkus BES |
|
2 |
418 |
Phase II |
PE-CERTIFIED |
|---|---|---|---|
|
Towers Inspected: |
Residential Units: |
Inspection Depth: |
Deliverable: |
The Challenge: High-Rise Buildings, 40-Year-Old Concrete, and a Coastal Environment
Two 18-story condominium towers on Marco Island, Florida, built in the early 1980s and housing 209 residential units each, had reached a defining moment. Under Florida’s landmark Senate Bill 4-D (the “Building Safety Act”) and Florida Statutes, these towers are required to undergo a formal Milestone Inspection conducted by a licensed Florida Professional Engineer. For buildings located within three miles of the coastline, local enforcement agencies may require the initial inspection to be completed when the building reaches 25 years of age, rather than the 30-year default, with subsequent inspections to follow every 10 years. The inspections must evaluate the structural integrity of major building components, identify any substantial structural deterioration, and determine whether any conditions rise to the level of “unsafe” or “dangerous” as defined by the Florida Building Code.
For a pair of 40-plus-year-old concrete towers situated in a coastal saltwater environment, the stakes could not have been higher. Decades of exposure to humidity, salt air, and the cumulative effects of deferred maintenance had created conditions that posed real risk to the structural integrity of key building systems. The association needed a partner with the technical depth to conduct both a Phase I visual survey and, where warranted, the more invasive Phase II destructive investigation required to fully characterize the extent of structural deterioration.
“In a coastal high-rise, the damage you cannot see is often more consequential than the damage you can. A Phase II investigation is not optional when balconies and stairs exhibit the warning signs these buildings showed.” – Craig M. Dudas, RS, Rimkus Senior Practice Leader, Construction Advisory
The engagement also carried an important legal dimension: the certified reports would be submitted to both the condominium association and the local Authority Having Jurisdiction (AHJ). The findings would directly inform the association’s legal obligations, its repair timeline, and its responsibility to residents. Getting the assessment right was not just a technical requirement – it was an obligation of care.
The Solution: A Multidisciplinary Phase I and II Milestone Inspection
The Rimkus Built Environment Solutions (BES) group was engaged to deliver a complete structural Milestone Inspection covering both Phase I and Phase II requirements across Tower 3 and Tower 4. The engagement was prepared to comply with Florida Senate Bill 4-D and Florida Statutes, with findings certified by licensed Florida Professional Engineers.
Our team of experts included structural engineers, concrete restoration experts, and assessment specialists to help the client identify deterioration and evaluate the structural significance of the buildings with precision.
|
Phase I Visual Survey |
Phase II Destructive Investigation |
|
Comprehensive visual examination of all major structural components across both 18-story towers, including exterior walls, columns, beams, floor systems, balconies, walkways, stairs, foundation, and interior units. |
Limited destructive investigation of accessible structural components to characterize the nature and extent of substantial structural deterioration identified during the Phase I survey. |
|
Acoustical Emissions Testing |
PE-Certified Statutory Reporting |
|
Mechanical sounding of concrete surfaces using lightweight hammers and delamination detection tools to identify debonded, spalled, and deteriorated concrete beneath surface finishes across balconies and walkways. |
Certified reports issued to the condominium association and the Authority Having Jurisdiction, meeting all requirements of Florida Statute including damage matrix exhibits and photographic documentation. |
What the Inspections Found: Significant Deterioration Across Critical Systems
The field observations conducted across multiple site visits spanning October 2021 through April 2023 revealed a consistent and serious pattern of structural deterioration, particularly in the building systems most exposed to the coastal environment. The findings were substantially similar across both Tower 3 and Tower 4, reflecting the identical construction, age, and exposure conditions of the two buildings.
|
Structural Component |
Condition |
Key Findings |
|
Exterior Walls |
Good |
Stucco cracking, unsealed penetrations, and hollow-sounding stucco at parapet walls and slab edges. Water intrusion risk but not structurally significant. |
|
Columns and Beams |
Good |
Generally sound with isolated cracking. No indications of substantial structural damage. Majority of elements are not fully visible. |
|
Floor System |
Good |
Concrete spalls with exposed rebar found in rooftop mechanical room and 15th-floor storage areas. No substantial structural damage present. |
|
Exterior Balconies |
Fair |
Hollow sounding, spalling concrete, rebar corrosion, cracking exceeding ACI 224R tolerances, failed waterproofing, and rust spots. Structurally significant damage requiring immediate repair. |
|
Exterior Walkways |
Good |
Hollow sounding, buckling tiles, concrete spalling, rebar corrosion, unbonded stucco, and unsealed penetrations. Structurally significant damage present. |
|
Stairs |
Fair |
Concrete spalling at landings, cracks exceeding ACI tolerances, and severe steel corrosion including 100% section loss in stringers, rail posts, and underside steel decks. Structurally significant. |
|
Foundation |
Good |
No indications of substantial structural damage. Majority of foundation is not visible during inspection. |
|
Interior Units |
Good |
Structural elements are generally not visible. No indications of substantial structural damage observed. |
|
Rooftop Mechanical Supports |
Poor |
Substantial corrosion with section loss in steel framing supporting cooling towers. Classified as UNSAFE and DANGEROUS under the Florida Building Code. |
Findings Requiring Additional Attention
The balcony findings warranted particular attention. Acoustical emission testing (sounding) detected hollow areas across balcony decks on both towers, a condition indicative of concrete delamination or debonded tile adhesion. Where selected balcony tiles were removed for investigation, spalling concrete was revealed beneath, caused by inadequate cover over the embedded steel reinforcement. Corrosion-related cracking at slab surfaces, slab edges, and knee-walls was widespread, exceeding the American Concrete Institute’s tolerable crack width threshold of 0.012 inch for elements exposed to humidity and moist air.
The stair systems presented conditions of comparable severity. Steel stringers, rail posts, and landing decks exhibited corrosion ranging from surface rust to complete section loss, meaning some structural steel members had lost their entire load-bearing cross-section to corrosion. This represented a life safety concern for any resident using the stairwells.
The most urgent finding on both towers was the condition of the rooftop cooling tower supports. The steel framing supporting the mechanical equipment exhibited substantial corrosion with section loss, meeting the statutory definitions of both “unsafe” and “dangerous” under the Florida Building Code. This finding required immediate action.
The Inspection Process: Rigor Across Multiple Site Visits
The inspection program for both towers was conducted across multiple site visits to provide thorough coverage of all structural systems in varying access conditions. The multi-visit approach allowed the team to return to specific locations of concern, conduct destructive investigation where Phase I findings warranted it, and build a complete picture of each building’s structural condition before finalizing the reports.
Phase 1: Visual Survey (October 2021, November 2021)
Initial visual examination of habitable and non-habitable areas across both towers. Observations covered exterior walls, columns, beams, floor systems, balconies, walkways, stairs, foundation, and interior units to the extent accessible and within view. Photographic documentation captured at all areas of observed concern.
Additional Site Visits (February 2022, November 2022, April 2023)
Return visits to conduct follow-up observations, acoustical emissions testing using lightweight hammers and delamination detection tools, and limited destructive investigation in areas where substantial deterioration was identified during Phase I. Crack and damage mapping prepared to document approximate locations and estimated quantities of distress.
Phase II: Destructive Investigation
Selected demolition at balcony locations to expose underlying concrete conditions. Investigation confirmed the presence of spalled concrete beneath tile finishes, insufficient cover over embedded reinforcement, and active rebar corrosion. Findings were incorporated into the damage matrix and photographic exhibits included in the final reports.
Report Preparation and PE Certification
Comprehensive reports prepared for each tower meeting all statutory requirements under Florida Statute Reports include field observations, engineer’s opinions and recommendations, damage matrix exhibits, and photographic documentation. Certified and digitally signed and sealed by a licensed Florida Professional Structural engineer, and submitted to both the condominium association and the local Authority Having Jurisdiction.
The Value Delivered: Safety, Clarity, and a Documented Path Forward
The Rimkus BES engagement delivered value across four dimensions: immediate life safety protection, regulatory compliance, informed decision-making for the board, and a documented baseline for long-term remediation planning.
Immediate Life Safety Action
The Developer Transition Study gave the association a professionally documented, PE-certified record of construction conditions at the moment of transition. This documentation is the foundation of any future defect claim under Florida’s Chapter 558 process. Without it, defects discovered years later are far harder to attribute to the developer, and far more expensive to remediate without recourse. By identifying defects early and systematically, the association preserved its legal standing and its ability to seek remediation from the responsible parties.
Regulatory Compliance with Evidentiary Quality
The certified Phase I and Phase II reports, signed and sealed by a licensed Florida Professional Structural Engineer and submitted to the Authority Having Jurisdiction, gave the association a legally defensible record of compliance with Florida’s Milestone Inspection statute. This documentation protects the board from liability exposure related to deferred inspection obligations and creates a formal record that will be essential if the association pursues any construction defect claims or insurance remedies related to the deterioration found.
Informed Capital Planning at Critical Scale
The findings across both towers, particularly the breadth of balcony and stair deterioration, signal the need for large-scale remediation that will require significant capital investment. The damage matrix and photographic exhibits produced as part of the reports give the association and its engineers the baseline data needed to scope repair specifications, solicit contractor bids, and prioritize work by structural significance. Without this documented baseline, the association would be managing remediation in the dark.
A Framework for Ongoing Maintenance and Risk Management
The Rimkus reports also identify a range of conditions that, while not rising to the level of substantial structural deterioration, require routine maintenance attention: stucco cracking, unsealed penetrations, failed sealants, and waterproofing degradation. These are the conditions that, left unaddressed, become the structural deficiencies of the next inspection cycle. By documenting them now, the reports give the association a maintenance checklist with direct structural relevance.
Why Choose Rimkus Built Environment Solutions?
Structural Milestone Inspections for aging high-rise concrete buildings in coastal environments are among the most technically demanding assessments in the built environment. They require engineers who understand post-tensioned concrete floor systems and the mechanics of corrosion-induced deterioration, who can conduct and interpret acoustical emissions testing and destructive investigation, and who can translate complex field findings into statutory language that satisfies both engineering rigor and legal defensibility.
The Rimkus BES team that delivered this engagement represented exactly that combination: a Practice Leader for Restoration with structural engineering and special inspection credentials, a Vice President that is a licensed Florida PE and reserve specialist, a Practice Leader for Assessments, and a licensed Florida PE, all working under a single project number with unified methodology and accountability.
For condominium associations, property managers, and legal counsel facing the obligations of Florida’s Milestone Inspection statute, the quality of the inspection team determines the quality of the outcome. Rimkus BES brings the technical depth, the process discipline, and the statutory knowledge to deliver inspections that protect people, inform decisions, and hold up under scrutiny.
Key Takeaways for High-Rise Condo Associations and Property Managers
If your association manages aging high-rise buildings in a coastal environment, keep the following key principles in mind when conducting Milestone Inspections.
What Every High-Rise Condo Association Should Know
- Phase I alone may not be enough. When visual inspection reveals hollow sounding, spalling, corrosion, or cracking at or above ACI tolerance thresholds, proceeding to Phase II destructive investigation is necessary to fully characterize the extent of structural deterioration.
- Balconies and stairwells are the highest-risk systems in aging coastal concrete buildings. Inadequate rebar cover, decades of salt air exposure, and deferred waterproofing maintenance create conditions that can progress from cosmetic to structurally significant faster than most associations recognize.
- A finding of “unsafe” or “dangerous” requires immediate action. Florida’s Milestone Inspection statute is designed to surface exactly these conditions. When a PE makes this determination, the association’s legal and safety obligations are clear and non-negotiable.
- The damage matrix and photographic documentation produced by a thorough SMI are not just compliance records. They are the technical foundation for repair specifications, contractor procurement, and capital planning at scale.
- A multidisciplinary inspection team outperforms a single inspector. Structural engineers, restoration specialists, and assessment professionals see different things and bring different frameworks to the same set of conditions. The quality of the team directly determines the quality of the findings.
- Routine maintenance documented and deferred becomes substantial structural deterioration. The gap between a stucco crack that needs sealing and a balcony slab that needs structural repair is often just a few seasons of neglect in a coastal environment.
Meet Our Florida Expert: Craig M. Dudas, RS
Senior Practice Leader, Construction Advisory
Built Environment Solutions, Florida
+1 813 521 5020
[email protected]
View Craig’s Expert Profile
Craig leads structural milestone inspections, restoration assessments, and building envelope evaluations for condominium associations across Florida, bringing decades of construction, engineering, and forensic expertise to boards navigating complex compliance challenges.
Connect with Craig directly or submit a request for consultation today!
This case study is intended to provide general information and insights into prevailing industry practices. It is not intended to constitute, and should not be relied upon as, legal, technical, or professional advice. The content does not replace consultation with a qualified expert or professional regarding the specific facts and circumstances of any particular matter.