What SB 4D Requires
In the wake of the Champlain Towers South collapse in Surfside in June 2021, the Florida Legislature passed Senate Bill 4D (SB 4D), establishing mandatory milestone structural inspections for aging condominium and cooperative buildings across the state. The law applies to any condominium or cooperative building that is three stories or taller, with inspection timelines determined by the building's age and proximity to the coast.
Buildings located within three miles of the Florida coastline must complete their first milestone structural inspection when the building reaches 25 years of age. Buildings further inland have until 30 years. After the initial milestone inspection, follow-up inspections are required every 10 years for the life of the building. The inspection must be conducted by a licensed professional engineer or a licensed architect and consists of two phases: Phase One is a visual examination of the building's structural components, and Phase Two — triggered only if Phase One identifies substantial structural deterioration — involves a more detailed assessment that may include destructive and non-destructive testing.
For condo associations and HOA boards, the law creates a non-negotiable compliance deadline. Buildings that have already passed their age threshold must complete inspections promptly. Buildings approaching the threshold need to begin planning now, as scheduling qualified engineers and coordinating building access takes time — particularly in South Florida markets where demand for inspection services has surged.
The Role of Visual Documentation in Milestone Inspections
The Phase One milestone inspection requires the licensed engineer or architect to visually examine the building's structural components — including load-bearing walls, floors, foundations, roof structures, and exterior elements like balconies, railings, and facade systems. For multi-story buildings, this visual examination presents a logistical challenge: how do you thoroughly inspect the exterior of a 10-story or 20-story building from the outside?
Traditionally, this has required scaffolding, boom lifts, or rope access — methods that are expensive, time-consuming, and create safety risks. Drone visual documentation offers a practical alternative for the exterior assessment component. A drone equipped with a high-resolution camera can capture every facade, balcony, window seal, concrete surface, and roofing element from multiple angles and distances in a fraction of the time required by physical access methods.
The resulting imagery provides the inspecting engineer with a comprehensive visual record of the building's exterior condition before and during the inspection process. Engineers can review the drone imagery to identify areas of concern — spalling concrete, cracked stucco, corroded reinforcing steel, water staining patterns, balcony railing deterioration — and then focus their physical examination time on the areas that most warrant closer inspection. This makes the overall inspection process more efficient and more thorough, because the engineer can see the entire building exterior at high resolution rather than examining only the areas accessible from the ground or from specific lift positions.
What a Drone Inspection Provides (and What It Does Not Replace)
It is critical to understand the boundary between what drone documentation provides and what it does not replace. Drone visual documentation provides high-resolution exterior imagery of the building — photographs that are GPS-tagged, timestamped, and organized by building face and elevation. This imagery captures visible surface conditions: concrete spalling, crack patterns, staining, vegetation growth, flashing deterioration, gutter and drainage conditions, balcony surface wear, and railing integrity.
What drone documentation does not provide is a structural engineering assessment. The drone cannot determine the internal condition of concrete, measure reinforcing steel corrosion depth, assess the load-bearing capacity of structural elements, or evaluate conditions behind walls and cladding. These assessments require a licensed professional engineer using engineering judgment, physical examination, and where necessary, destructive and non-destructive testing methods specified in the Phase Two inspection process.
Think of drone documentation as the eyes of the inspection — it shows what is visible from the outside at a level of detail that would be extremely difficult and expensive to achieve through other means. The licensed engineer remains the brain of the inspection — interpreting what the imagery shows, determining what requires closer examination, and rendering the professional judgment that the milestone inspection law requires. The two work together: the drone provides comprehensive visual input, and the engineer provides the professional analysis.
Cost and Timeline for Drone Documentation
Drone documentation for milestone inspection support typically starts at $500 for a single building, with pricing varying based on the building's height, footprint, number of faces requiring documentation, and any special access considerations such as proximity to airports or restricted airspace. Multi-building condo communities and large HOA properties receive package pricing that reflects the efficiency of documenting multiple structures in a single site visit.
On-site flight time for a single mid-rise building is typically 30 to 90 minutes. The drone captures imagery of all four building faces, the roof surface, balconies, and any ground-level structural elements visible from above. Deliverables are processed and delivered within 48 hours of the flight, consisting of an annotated PDF report organized by building face and a complete set of high-resolution GPS-tagged photographs delivered via cloud link.
For condo associations planning their milestone inspection timeline, we recommend scheduling drone documentation before the engineer's site visit. This allows the engineer to review the aerial imagery in advance, identify areas of concern remotely, and arrive on site with a focused examination plan. This sequencing saves the engineer time and may reduce the overall cost of the engineering inspection by making the on-site examination more targeted and efficient.
How to Get Started
If your building is approaching its milestone inspection deadline — or has already passed it — drone documentation is a practical first step that accelerates the process and provides lasting visual records for the association's files. The documentation we produce supports the inspecting engineer's work and creates a baseline visual record that will be valuable for comparison during future inspection cycles.
Contact us with your building address, height, and approximate age, and we will provide a scope and pricing within one business day. We coordinate directly with your inspecting engineer if you have already engaged one, or we can provide the documentation independently for your association's records.