Seawall cap repair.
Read the rust before you patch.

Is a cracked seawall cap a repair or a warning sign?

The cap is the concrete beam along the top of the wall. It ties the panels together and often carries docks, davits and lifts.

Salt water and spray drive chloride into the concrete. When the steel inside rusts, it swells and cracks the concrete from within. That is why rust stains matter more than hairline cracks.

When should I call about seawall cap damage?

• Concrete is flaking off and steel is showing.
• A crack runs along the cap with orange-brown rust stains.
• The cap has cracked at a davit, lift or dock connection.
• A joint in the cap has opened, or one section has dropped.
• The cap is pulling away from your patio or pool deck.
• You plan to add a lift, a davit or a wider deck on the cap.

What does each kind of seawall cap damage mean?

What are the seawall cap repair options?

• Crack sealing: for fine, stable cracks, to keep water and salt out.
• Spall repair: remove loose concrete, clean or replace rusted steel, then patch with repair mortar.
• Joint repair: reseal or rebuild open joints in the cap.
• Partial cap replacement: cut out and recast failed sections. Key West’s 2019 seaport job replaced 61 feet of cap at Schooner Wharf alongside void fill and epoxy repairs. Key West ITB 19-017
• Encasement: cast new reinforced concrete over the old face. Key West’s 2017 Half Shell repair used a casting at least 8 inches thick. Key West ITB 17-019
• New cap: Florida’s exemption list includes a new cap used only to stabilize and repair a seawall, if it does not block navigation. Rule 62-330.051(12)

A patch lasts only if the steel behind it is sound. Ask how much steel will be exposed and checked before the price is final.

Can my seawall cap carry a boat lift or davit?

Lifts and davits put heavy point loads on the cap. Several Keys codes treat that as an engineering question.

• Key Colony Beach lifts: an elevator lift attached to a cap or dock must be engineer-certified at 120% of lift plus boat weight, and the forks may not rise above the cap. KCB Code 5-43
• Key Colony Beach davits: the base must be certified for 120% of rated capacity plus davit weight, and davits over 5,500 pounds need Commission approval. KCB Code 5-42
• Marathon: a lift beside a dock or seawall may rise no more than 5 feet above the highest walking surface of the dock or cap. Marathon code 104.64
• Monroe County: davits sit at least 5 feet from the side property lines extended into the water. Monroe County code 118-12(m)(3)

Plan the lift and the cap together. The docks and lifts guide covers the permits.

How wide can a seawall cap be in the Keys?

Neighbors a few miles apart work to very different rules. A Key Colony Beach cap can be up to five times as wide as Marathon’s limit, so check before you widen a cap into a patio. See the Key Colony Beach and Marathon guides. Marathon’s rules also cover Grassy Key and Coco Plum. Marathon Charter, Sec. 10

Should I raise my seawall cap while I am at it?

Key Colony Beach sets a cap height in its code: 5.5 feet above mean sea level for the first wall on a canal, or match the higher adjoining wall. KCB Code 5-51 That “mean sea level” is an older datum, so have a surveyor convert it to NAVD 88 first. NOAA datum definitions

Monroe County plans for 10 to 17 inches of sea-level rise from 2000 to 2040, but its resiliency page sets no private seawall height. Monroe County resiliency At Vaca Key, NOAA measures a rise of about 1.7 inches per decade since 1971. NOAA sea level trends

Public walls give reference points. Key West’s 2018 Irma repair at Mallory Square set its new cap at 5.0 feet NAVD 88, and its funding request for the Southernmost Point seawall listed a higher cap for sea-level rise. Key West ITB 18-036 Florida Senate LFIR 1134

• Get elevations for your cap and both neighbors’ caps in the same datum.
• Ask how a taller cap changes the load on old panels and tie rods.
• In V and Coastal A flood zones, expect the analysis Monroe County requires showing the wall will not push water onto neighbors. Monroe County code 122-31(d)
• Plan the joint where your cap meets a lower neighbor.

See seawall height requirements for more.

Do I need a permit for seawall cap repair in the Keys?

The state exempts a new cap used only to stabilize and repair a wall, but the local permit still applies. Rule 62-330.051(12)

What does seawall cap repair cost?

Cap work is priced by length, depth of damage and access. The only public Keys line items come from Key West’s 2019 seaport bid.

There, four contractors priced 333 feet of new reinforced concrete cap at roughly $435 to $800 a foot, as one part of a larger job. ITB 19-017 bid sheet That was a new cap on new sheet pile, so a home patch will price differently.

• Length of cap, and how much steel must be exposed and replaced.
• Removing and resetting docks, davits and lifts.
• Access by land or barge.
• Permit fees, compared office by office on the replacement page.

Build a like-for-like comparison with the cost guide.

What to ask before you sign for cap repair

• What caused the damage, and is the wall below sound?
• How much concrete comes out, and how will you check the steel?
• What repair material will you use, and why for salt water?
• Will docks, lifts or davits come off, and who resets them?
• Does the price include the permit and the final inspection?
• What does the warranty cover if the cracks return?

Seawall cap repair questions

Can I patch a spalling seawall cap myself?

Small cosmetic work may be possible, but cap repair is structural and the Monroe County exemption excludes structural work. Monroe exemption notice In Marathon, owner-builder permits are only for property you use yourself, not property for sale or lease. Marathon Building FAQ

Can I widen my seawall cap into a patio?

Check your city first. Marathon allows a 2-foot cap, while Key Colony Beach requires 5 to 10 feet. Marathon code 106.36 KCB Code 5-52

Does a new cap need a state permit?

Often not. Florida exempts a new cap used only to stabilize and repair a seawall when it does not block navigation. Rule 62-330.051(12) You still need the local permit.