For years, the downstairs enclosure beneath a stilt home in unincorporated Monroe County came with a number that every local homeowner seemed to know: 299 square feet. That limit shaped renovation plans, storage decisions, property inspections, and more than a few conversations during real estate transactions. Now, the rule has changed, and the change is substantial.
As of February 4, 2026, unincorporated Monroe County has removed its longstanding 299-square-foot cap for qualifying enclosures beneath elevated homes. The county also eliminated its mandatory downstairs-enclosure inspection at the time of sale and discontinued the related Floodplain Certificate of Compliance Program.
That sounds like homeowners have suddenly been given a blank check to build whatever they want beneath their homes. They have not.
The extra space can create valuable storage, parking, and access opportunities, but federal floodplain rules still limit how it may be used. The downstairs area does not become another bedroom, guest suite, apartment, or air-conditioned family room simply because the square-footage restriction disappeared.
Let’s walk through what actually changed, what stayed firmly in place, and what Florida Keys owners and buyers should investigate before making plans.
The 299-Square-Foot Rule Is Finally History
The old rule was more than a minor design restriction. For many owners of elevated homes, it meant that only a small portion of the area beneath the structure could be enclosed, even when the home’s footprint left considerably more covered space available.
Monroe County’s updated code removes that local size limit for downstairs enclosures in unincorporated Monroe County. In practical terms, a qualifying owner may now be able to enclose more or potentially all of the area beneath an elevated home, provided the project complies with the remaining building, floodplain, zoning, and permitting requirements.
Why the Old Limit Existed
The restriction was tied to floodplain management and Monroe County’s participation in the National Flood Insurance Program. Homes in vulnerable flood zones are commonly elevated so that the primary living area sits above the required flood elevation.
The area below that elevated floor is expected to remain flood-resistant and serve only limited purposes. FEMA defines an enclosure as a walled-in area beneath the lowest floor of an elevated building and states that areas below the Base Flood Elevation may be used only for parking, building access, and storage.
Bedrooms and Guest Suites Are Still Off the Table
Removing the square-footage limit does not legalize downstairs bedrooms, apartments, recreation rooms, home offices, or other living areas below the required elevation.
A space can look finished and still be noncompliant. Flooring, finished walls, built-in cabinetry, climate control, bathrooms, or furnishings may cause an enclosure to appear and function like living space, even when it is described as “storage.” That can create problems with permitting, code enforcement, flood insurance, financing, and a future sale.
Flood-Resistant Construction Still Matters
The enclosure must continue to meet the applicable structural and floodplain standards. In many flood zones, that includes appropriate flood openings designed to allow water to enter and exit rather than placing dangerous pressure on the walls.
FEMA guidance generally requires enclosed areas in qualifying A Zones to include at least two openings positioned on different walls, with sufficient net open area to equalize hydrostatic flood forces. Coastal V Zones may also require breakaway-wall construction and professional design certification. The exact requirements depend on the property’s flood zone and project details.
This is not the place for a casual weekend project completed without plans or permits. The enclosure is part of a flood-exposed structure, and the wrong materials or construction method can turn walls and stored belongings into debris during a major storm.
Mechanical Equipment Needs Special Attention
Utilities and service equipment located below the Base Flood Elevation are heavily regulated because they can be damaged by floodwater and may affect flood-insurance treatment.
FEMA states that utilities and service facilities associated with an enclosure must be designed or located to prevent flood damage. Before adding electrical components, appliances, plumbing fixtures, mechanical systems, or air-conditioning equipment, owners should obtain property-specific guidance from Monroe County and qualified building professionals.
The safest assumption is not that a particular feature is automatically allowed, but that every proposed installation needs to be reviewed against the current flood zone, elevation, permit history, and code.
The Time-of-Sale Inspection Requirement Is Gone
The size limit was not the only major change. Monroe County also removed the local requirement for a downstairs-enclosure inspection before transferring ownership of an affected elevated property.
Under the previous program, certain homes with below-base-flood enclosures were subject to a county-approved inspection shortly before a sale. The inspection was intended to identify illegal improvements, nonconforming construction, or prohibited uses and document those findings for the county and the purchaser.
Ordinance 023-2025 eliminated that inspection requirement and the accompanying Floodplain Certificate of Compliance Program. The amendments took effect on February 4, 2026.
Location Still Determines Which Rules Apply
One common mistake is assuming every Florida Keys property follows the same local rules. The new rule applies specifically to unincorporated Monroe County. Incorporated municipalities, including Marathon, Key Colony Beach, Islamorada, Key West, and Layton, may follow their own building and land-development regulations.
Marathon and Key Colony Beach already handled downstairs enclosures differently, so homeowners there may not experience the same level of change as residents in unincorporated Monroe County.
Confirm the Governing Jurisdiction First
A mailing address does not always tell you which building department governs a property. Before planning or evaluating an enclosure, confirm whether the home is in unincorporated Monroe County or an incorporated municipality, then verify the current rules with the appropriate local departments. This matters because nearby properties can still have different zoning, permitting, flood-zone, and enclosure requirements.
What Homeowners Should Do Before Enclosing More Space
The rule change creates new possibilities, but homeowners should understand the property and permitting requirements before starting construction.
Review the Existing Permit History
Start by checking whether existing enclosures, stairs, walls, electrical work, and other improvements appear in official records. Monroe County provides public permit and code-compliance resources, although older records may require additional research. Remember, an existing enclosure is not automatically a permitted enclosure, and purchasing a home does not confirm that every improvement received approval.
Speak With the Building Department Before Designing the Project
Confirm what permits, plans, engineering, flood openings, materials, agreements, and inspections may be required before finalizing the project. Monroe County also uses nonconversion agreements for certain downstairs enclosures. These agreements generally confirm that the enclosed area will not later be converted into unauthorized living space.
Talk With the Flood-Insurance Professional Early
A downstairs enclosure can affect how a property is evaluated for flood insurance, particularly if its design, openings, equipment, or use do not meet applicable requirements.
Homeowners should speak with a licensed flood-insurance professional before construction rather than waiting until the project is finished or the home is under contract. The impact can vary based on flood zone, elevation, building age, enclosure design, and policy details.
For a conversational overview of why this Monroe County change matters, watch Nate Bartlett’s accompanying YouTube video.
More Freedom Downstairs With Important Boundaries
Removing the 299-square-foot limit is a meaningful win for many owners of elevated homes in unincorporated Monroe County. It can create more room for storage, parking, storm preparation, and the equipment that naturally accumulates when you live in the Florida Keys.
The most important part of the announcement, however, is what it does not do.
It does not create legal living space below the required flood elevation. It does not excuse unpermitted work. It does not remove FEMA’s restrictions, flood-resistant construction standards, or the need for county approval. And although the former inspection-at-sale program has ended, buyers still need to understand exactly what they are inheriting.
As a Florida Keys real estate professional based in Marathon, Nate Bartlett helps buyers and sellers look beyond the obvious square footage and understand the permitting, floodplain, and ownership details that can shape a transaction. A downstairs enclosure can be a useful asset, but only when its history, construction, and legal use are clear.
Planning to buy or sell an elevated home in the Florida Keys or wondering how these changes may affect your property? Contact Nate Bartlett for a practical local conversation about the home, its enclosure, and the questions worth answering before your next move.
FAQs
Can I now enclose the entire area beneath my Florida Keys home?
Potentially, if the property is in unincorporated Monroe County and the enclosure meets all building, zoning, structural, and floodplain requirements.
Can the expanded downstairs enclosure be used as a bedroom?
No. These spaces are generally limited to storage, parking, and building access, not bedrooms, apartments, or other living areas.
Do I still need an enclosure inspection when selling my home?
Monroe County removed the former mandatory inspection-at-sale requirement in affected unincorporated areas, though buyers may still request inspections and review permit records.
Does the rule change legalize an enclosure that was built without permits?
No. Unpermitted construction or illegal living space may still require permitting, correction, or removal.
Does this change apply in Marathon and every Florida Keys municipality?
No. The amendment applies to unincorporated Monroe County. Incorporated municipalities may follow different rules and permitting procedures.
About Nate Bartlett
Nate Bartlett serves buyers and sellers throughout Key Colony Beach and the Florida Keys, helping clients navigate one of Florida’s most unique coastal real estate markets with clarity and confidence. His team specializes in waterfront properties, coastal real estate, relocation assistance, pricing strategy, market analysis, and personalized client service.
With more than 60+ five-star Google reviews, over $60 million in closed sales volume across coastal and waterfront properties, Berkshire Hathaway’s Chairman’s Circle Award recognition, and Best Realtor of 2025 honors in the Best of Marathon Awards, Nate Bartlett continues helping clients buy and sell throughout the Florida Keys with local expertise and a practical understanding of what makes coastal homes truly valuable.