When does a seawall need replacing?
Replacement makes sense when damage runs along most of the wall, when what holds it up has failed, or when repairs keep coming back. In the Keys, it also means planning around strict footprint and open-water rules.
Age is a clue, not a verdict. Most Key Colony Beach walls were designed for about 30 years, and the city says many have reached or passed that. KCB Seawall Owner’s Manual
- The wall leans along much of its length.
- Panels are cracked through at the waterline in several places.
- Sinkholes keep coming back after repairs.
- The toe is exposed or undermined along the length.
- A Key Colony Beach notice of an unsafe or deteriorated seawall. KCB Ord. 2026-509
- You are buying a vacant lot: the Key Colony Beach manual says to evaluate the seawall right away and rebuild as needed. KCB Seawall Owner’s Manual
Can I replace my seawall in the same place?
Usually yes, and often you must. Monroe County lets lawful, deteriorated walls be repaired or replaced, but they must keep the existing footprint as far as practicable. Monroe County code 118-12(k)(4) You may need to show the wall was permitted or predates permitting.
| Rule | Limit | Where it applies |
|---|---|---|
Monroe County code 118-12(k)(4) Monroe County code 118-12(k)(4) | Existing footprint, to the maximum extent practicable | Unincorporated Monroe County |
Marathon code 108.20 Marathon code 108.20 | Existing footprint; on open water only if riprap with filter cloth is not feasible | Nonconforming walls in Marathon |
KCB Code 5-50 KCB Code 5-50 | Cap edge on the platted property line; a wall in front needs a variance | Key Colony Beach |
Rule 62-330.051(12) Rule 62-330.051(12) | At the old line, landward, or up to 18 inches waterward if damaged within the last year | State environmental review |
Rule 18-20.004 Rule 18-20.004 | Up to 1 foot waterward without a consent application | Aquatic preserves, such as Coupon Bight off Big Pine Key DEP Coupon Bight page |
Rule 18-21.005 Rule 18-21.005 | Letter of consent for a wall up to 3 feet waterward of mean high water | Where the state owns the bottom |
In 2021 the Key Colony Beach building official told the planning board he expected requests to build new sheet pile in front of failing walls “often”. KCB planning board minutes, July 2021 Key West takes that approach at its own marina: the Charter Boat Row plan drives new sheet pile waterward of the old wall and leaves the old one in place. Key West capital plan GB75511701
Can I build a new seawall on open water in the Keys?
Generally not. Ocean and bay frontage is where the Keys codes are strictest.
| Where | Rule | Source |
|---|---|---|
Unincorporated Monroe County | No new seawalls or hardened vertical structures on open water. New canal walls only for severe erosion where plants or riprap will not work. | |
Key West | Hardening only for a critical peril after plants fail. Riprap first, generally no vertical walls, and nothing waterward of mean high water except in the public interest. | |
Marathon | No new vertical walls on open water. Elsewhere, hard walls only where riprap will not do, as the City Biologist decides. | |
Layton | Plan policy calls for riprap, plants or cantilevered platforms instead of vertical bulkheads. | |
Key Colony Beach | Seawalls required wherever state or federal agencies allow them. Sloping seawalls are not allowed. |
The county code keeps seawalls and riprap off any beach berm that is a known or potential turtle nesting area. Monroe County code 118-12(k)(7) In V and Coastal A flood zones, Monroe County, Key West and Marathon also want a design professional’s analysis that the wall will not push floodwater or waves onto neighbors. Monroe County code 122-31(d) Key West Code 34-139(7) Marathon code 107.102.11
What are Key Colony Beach’s seawall rules?
Key Colony Beach has its own seawall design code. If you own there, your engineer works to these rules:
- Height: 5.5 feet above mean sea level for the first wall on a canal; otherwise match the higher adjoining wall. The datum is an old one, so have a surveyor convert it to NAVD 88. KCB Code 5-51
- Cap: 5 to 10 feet wide. KCB Code 5-52 to 5-55
- Frontage: the full water frontage of the lot, built at one time, not in sections.
- Shape: no sloping seawalls, and return slabs at least 5 inches thick where a wall end does not meet another wall.
- Tiebacks: rods at least 5/8 inch, fully coated with bituminous coating.
- Barge bond: $50,000 before any water-borne equipment enters the city. KCB Code 5-61
- Plans: signed and sealed by a Florida-licensed engineer. KCB Code 6-45
After a written notice of an unsafe seawall, a Key Colony Beach owner has 15 days for safety measures and 60 days for an engineer’s evaluation. Permit applications are due within 120 days, and repairs must finish within 12 months of approval. KCB Ord. 2026-509 Missing them can cost a vacation rental license. KCB Code 6-45
See the Key Colony Beach guide for the full local picture.
Which seawall material fits a Keys lot?
Material follows the site: water depth, what the wall bears on, access and the local code. Here is how the common options compare. Prices are left to the cost section, because they do not carry from lot to lot.
| Option | How it works | Keys notes |
|---|---|---|
Concrete panels with a poured cap | Precast panels set in a line and tied back to a buried deadman | The common Key Colony Beach wall: 6-inch panels, 5 to 8 feet wide. KCB manual |
Steel sheet pile with a concrete cap | Interlocking steel sheets driven in a line, tied back or cantilevered | Key West’s recent marina and seaport walls use it. Key West capital plan GB75512402 Key West ITB 19-017 |
Vinyl or composite sheet pile | Interlocking plastic or composite sheets with a concrete cap | Ask for calculations for your wall height and exposure, and for jobs the firm has done in salt water. |
Tie rods to a deadman | Steel rods run from the wall to a buried concrete anchor | Key Colony Beach requires rods of at least 5/8 inch with a bituminous coating. KCB Code 5-55 |
Augered or drilled rock anchors | Anchors drilled into firm ground or rock behind the wall, then grouted | Marathon inspects augered tiebacks as their own stage. Marathon inspection list |
Cantilever wall | No tie rods; the depth of the wall in the ground holds it | Key West’s Charter Boat Row plan calls for sheet pile without tie-backs. Key West capital plan GB75511701 |
Riprap revetment | Sloped rock instead of a vertical wall | Preferred or required on open water in most Keys codes. See riprap. |
How much does seawall replacement cost in the Keys?
Public prices for private canal walls are scarce here. The best benchmarks are Key West’s own waterfront bids, which include docks, design and hard access.
| Public job | Scope | About per foot |
|---|---|---|
Half Shell Raw Bar, 2017 | 245 feet of concrete fascia encasement, piles and a dock | $1,820 Key West ITB 17-019 |
Conch Republic wall, 2019 | 333 feet of new steel sheet pile and cap; wall line items only, low bid | $2,210 ITB 19-017 bid sheet |
Truman Annex, 2017 | About 370 feet of sheet pile with tiebacks in front of an old panel wall, design-build | $3,140 Key West RFP 004-17 |
LAB seawall, City Marina budget | 1,180 feet of T-pile wall replaced with sheet pile and cap | $3,900 construction budget Key West capital plan GB75512402 |
Mallory Square Aquarium, 2018 | About 177 feet of Irma-damaged sheet pile and cap, plus a footbridge | $4,620 Key West ITB 18-036 |
Spencer’s Boat Yard, 2024 | 189 feet of Truline 800 series wall with boatyard piers and platforms | $10,510 Key West ITB 24-014 |
None of these is a house on a canal. Use them as a ceiling, and as proof that Keys work costs more than national guides suggest.
Bids spread widely too. Key West’s 2025 Southernmost seawall drew eight bids, from $946,266 to $2,643,017. Key West ITB 25-010 Get at least three proposals on the same written scope.
Seawall permit fees on a $60,000 job
| Office | Rate (dollars per $1,000 of contract price) | Minimum or flat fee (dollars) | On a $60,000 contract, rounded |
|---|---|---|---|
Monroe County Res. 277-2025 Res. 277-2025 | Up to 62.18, scaled by which reviews apply | 236 flat under $5,000 | About $2,200 to $2,600, plus a $976 Notice to Proceed |
Key West Key West Code 14-2 Key West Code 14-2 | 36 | 100 minimum | About $2,200, plus about $200 in processing, surcharge and review fees |
Marathon Marathon Res. 2025-73 | 17.50 | 93.50 minimum | About $1,100 with the education fee and surcharges |
Key Colony Beach KCB Res. 2026-01 KCB Res. 2026-01 | 35 above the first $2,500 | 100 flat up to $2,500 | About $2,200 with the 2.5% surcharge |
Layton Layton permit report | Not posted | Not posted | Ask City Hall |
Monroe County’s fees adjust each October 1 for inflation after September 30, 2026, so recheck before you budget. Res. 277-2025 Starting work before the permit costs more everywhere: Monroe County adds a 100% penalty, Key West doubles the fee above $5,000, and Key Colony Beach charges triple fees plus $500. Res. 277-2025 Key West Code 14-2 KCB Res. 2026-01
Other Keys cost items
- Barge work. Developed lots often need it, and houses, docks, davits, trees, sprinklers and conduits add cost. Most Key Colony Beach walls are at least 75 feet long. KCB manual
- The $50,000 Key Colony Beach bond for water-borne equipment. KCB Code 5-61
- Longshore insurance. Monroe County’s Work Over the Water notice warns that federal longshore coverage may be needed, and that the owner may be liable if the contractor lacks proper insurance. Monroe Work Over the Water notice
- Benthic surveys by a biologist who holds a sanctuary permit. Sanctuary survey protocol
Build your own budget in the cost guide.
Which offices approve a seawall replacement in the Keys?
Expect several approvals, and expect the local permit to wait for the others.
- Local building permit from your city or Monroe County. County jobs also get Planning and Environmental review; that office is at (305) 289-2529. Monroe Planning and Environmental Resources
- Florida DEP: an exemption verification or a permit, from the Marathon office at (305) 289-7070. Canal walls often qualify for an exemption. DEP Marathon office Rule 62-330.051(12)
- State-owned bottom: written authorization where the state owns the bottom. Rule 18-21.005
- Army Corps, Keys Permits Section: (305) 526-7181. The Keys general permit SAJ-82 expired June 24, 2026, so ask which permit now covers your job. Army Corps Keys Permits Section Army Corps permit SAJ-82
- Marine sanctuary: a complete package of plans, state approval, seafloor (benthic) survey and federal approval, sent to fknms.authorizations@noaa.gov. Sanctuary nearshore permits
- Species review: on Big Pine Key, No Name Key and other species focus areas, a project may go to the U.S. Fish and Wildlife Service, with an $825 county fee when it does. Key deer assessment guide Res. 277-2025
- County Notice to Proceed: $976, after the state and federal approvals are filed. Monroe County code 118-12(k)(9) Res. 277-2025
The cities hold their permits the same way. Key Colony Beach issues a seawall permit only after Corps and DEP approval, and Marathon requires all federal and state approvals for shoreline work. KCB Code 5-30 Marathon code 106.38
In Key West’s historic district, exterior work needs a Certificate of Appropriateness filed with the building permit. Key West permits page The HARC guidelines do not list seawall standards, so ask Historic Preservation staff at (305) 809-3975. Key West historic district review Key West HARC division See the Old Town guide and the Big Pine Key guide.
How long does a seawall replacement take in the Keys?
| Step | Timing |
|---|---|
Seagrass survey, if needed Sanctuary survey protocol | Only June 1 to September 30. It may need redoing if work has not started within three years. |
Sanctuary application Sanctuary permits page | At least 90 days before the requested start |
Monroe County permit Monroe NTP handout | Expires within 180 days of issue unless the state and federal approvals are filed, per the county’s 2022 handout |
State review of rendered permits FloridaCommerce rendition | Up to 45 days before a rendered development order takes effect |
Key West completeness check Key West permit policy | Letter within 5 business days; 10 business days to fix |
Keeping a permit active Marathon inspection list Monroe inspections page | Marathon: an approved inspection every 180 days. County: a passed inspection within six months of issue. |
Key Colony Beach notice KCB Ord. 2026-509 | 120 days to file permits; 12 months after approval to finish |
The 2026 seagrass survey window closed on September 30. If your job needs a survey, the next window opens June 1, 2027, so line up the engineer and biologist this winter.
What to ask before you sign a seawall replacement contract
- Is the new wall in the existing footprint? If not, which rule allows the move?
- Which approvals does your price include: engineering, surveys, DEP, Corps, sanctuary?
- Will you work from land or a barge, and who posts any bond?
- Which anchoring system, and why for this lot?
- Is the old wall coming out, or staying behind the new one?
- What is your license? Florida certifies marine specialty contractors for seawalls. Rule 61G4-15.100 Monroe County also requires a Certificate of Competency in the trade; verify at (305) 289-2583. Monroe contractor page Monroe contractor page
- Does the contract include the Florida Homeowners’ Construction Recovery Fund notice? It is required on residential jobs over $2,500. F.S. 489.1425
The contractor check guide walks through each license lookup.
Seawall replacement questions
Can I put a new seawall in front of my old one?
Sometimes. The state allows restoration up to 18 inches waterward in some cases, but the county expects the old footprint where practicable. Rule 62-330.051(12) Monroe County code 118-12(k)(4) In Key Colony Beach it takes a variance from the location and height rules. KCB planning board minutes
Do I have to replace my whole seawall at once?
In Key Colony Beach, yes: the code requires a seawall along the full water frontage, built at one time. KCB Code 5-53 Elsewhere it depends on the engineer’s findings and the permit.
How long does a seawall last in the Keys?
Key Colony Beach says most of its walls were designed for a 30-year life. KCB manual Actual life depends on the steel, the drains, storm exposure and upkeep.
Show sourcesHide sources
- City of Key Colony Beach Seawall Owner's ManualSource reviewed 2026-10-28
- Code of Ordinances Ch. 6 Buildings, Art. II, Sec. 6-45 Seawall conditions; compliance requirements; enforcementSource reviewed 2026-10-28
- Monroe County Land Development Code, Chapter 118 - Environmental ProtectionSource reviewed 2026-10-28
- LDR Sec. 108.20 Nonconforming Docks And Shoreline Stabilization StructuresSource reviewed 2026-10-28
- Code of Ordinances Ch. 5, Art. III Marine Construction and Improvements, Docking of BoatsSource reviewed 2026-10-28
- Rule 62-330.051, F.A.C. (Exempt Activities)Source reviewed 2026-10-28
- Rule 18-20.004, F.A.C. (Management Policies, Standards, and Criteria - Aquatic Preserves)Source reviewed 2026-10-28
- Coupon Bight Aquatic PreserveSource reviewed 2026-10-28
- Rule 18-21.005, F.A.C. (Forms of Authorization)Source reviewed 2026-10-28
- Planning & Zoning Regular Meeting Minutes, July 21, 2021Source reviewed 2026-10-28
- City Marina at Garrison Bight Capital Projects (FY 25/26 CIP Project Detail, GB75511701)Source reviewed 2026-10-28
- Code of Ordinances, Subpart B Land Development Regulations, Ch. 110 Resource Protection, Art. IV Coastal ResourcesSource reviewed 2026-10-28
- LDR Sec. 106.36 Criteria For Approval (Hardened Shorelines)Source reviewed 2026-10-28
- Comprehensive Plan Amendment Package (Ord. No. 2022-11-01), adopted June 1, 2023Source reviewed 2026-10-28
- Monroe County Land Development Code, Chapter 122 - Floodplain ManagementSource reviewed 2026-10-28
- Code of Ordinances, Ch. 34 Floods, Sec. 34-139 Other developmentSource reviewed 2026-10-28
- LDR Sec. 107.102.11 Other DevelopmentSource reviewed 2026-10-28
- Executive Summary: Awarding of Contract for ITB #19-017 - Seawall Repairs (Resolution 19-217)Source reviewed 2026-10-28
- Permit and Inspection InformationSource reviewed 2026-10-28
- Executive Summary: Awarding of Contract for ITB #17-019 REBID: Half Shell Raw Bar Seawall Repairs - Key West Historic Seaport (Resolution 17-166)Source reviewed 2026-10-28
- ITB 19-017 Bids Spreadsheet (attachment to Resolution 19-217)Source reviewed 2026-10-28
- Executive Summary: Approve the Award of RFP 004-17 Truman Annex/NOAA Seawall Design-Build Construction to Ebsary Foundation CompanySource reviewed 2026-10-28
- City Clerk Interoffice Memorandum: Aquarium Seawall Repair Bid 18-036 (bid opening)Source reviewed 2026-10-28
- City Clerk Interoffice Memorandum: ITB 24-014 Spencer's Boat Yard Seawall (bid opening)Source reviewed 2026-10-28
- Memorandum: File ID 25-3925 - Award of Phase One Southernmost Seawall Project, ITB #25-010, to BDI Marine Contractors, LLCSource reviewed 2026-10-28
- Resolution No. 277-2025 (Building Department permitting fee schedule)Source reviewed 2026-10-28
- Building Fees (Code Sec. 14-1 and 14-2)Source reviewed 2026-10-28
- Resolution 2025-73, Exhibit A Permit Fee ScheduleSource reviewed 2026-10-28
- Resolution No. 2026-01 (Fee Schedule for Building Department Permits and Services)Source reviewed 2026-10-28
- Building Permit and Inspection Utilization Report, FY 2024/25Source reviewed 2026-10-28
- Work Over the Water NoticeSource reviewed 2026-10-28
- Resource Assessment Survey Protocols for Nearshore Construction ProjectsSource reviewed 2026-10-28
- Environmental ResourcesSource reviewed 2026-10-28
- SED Marathon OfficeSource reviewed 2026-10-28
- Jacksonville District Regulatory Office LocationsSource reviewed 2026-10-28
- Regional General Permit SAJ-82Source reviewed 2026-10-28
- Nearshore Construction PermitsSource reviewed 2026-10-28
- Key Deer Assessment Guide (July 2026)Source reviewed 2026-10-28
- LDR Sec. 106.38 Allowable ActivitiesSource reviewed 2026-10-28
- PermitsSource reviewed 2026-10-28
- Is My Property Under HARC Jurisdiction?Source reviewed 2026-10-28
- Historic Preservation Division (HARC)Source reviewed 2026-10-28
- PermitsSource reviewed 2026-10-28
- Notice To Proceed Instructional Handout (Internet Archive copy)Source reviewed 2026-11-05
- Instruction for Rendering Development Orders and Land Development RegulationsSource reviewed 2026-10-28
- Expedited Building Permit Policy & Procedures (Effective 1/01/2025)Source reviewed 2026-10-28
- InspectionsSource reviewed 2026-10-28
- Rule 61G4-15.100, Certified Specialty Contractors (final rule text, effective 8/28/2024)Source reviewed 2026-10-28
- Protect Yourself & OthersSource reviewed 2026-10-28
- Section 489.1425, Florida Statutes: Duty of contractor to notify residential property owner of recovery fundSource reviewed 2026-10-28