Can you dredge right up against an existing seawall?

Yes, carefully. We keep the cut back a controlled distance from the toe and grade toward the fairway so we don't undermine the wall. If the wall is questionable we survey it before the dredge to know exactly what it can take.

How long does a new seawall last if the canal keeps shoaling?

A properly designed seawall lasts 40 to 60 years, but that assumes the design bottom stays close to what it was engineered for. Repeated shoaling and prop wash can accelerate toe scour and cut that life significantly — which is why sequencing dredging with seawall work matters.

Do combined projects need one permit or two?

Usually two applications — one for the dredging and one for the seawall — but they can be filed and reviewed together as a coordinated package. FDEP, USACE, LWDD, and your municipality all still get their own say; we file it as one project so the reviews run in parallel.

What if we only need part of the seawall replaced?

Partial wall replacements are common — often the corner sections or a run that took the worst prop-wash exposure. We match new panels to the existing wall and tie them in cleanly, and coordinate the dredge cut so the new sections get proper toe embedment.

Are you the same company as South Florida Seawall?

Palm Beach Dredging is the marine dredging division of South Florida Seawall. Same ownership, same crews, same equipment — we split the two brands because dredging and seawall construction are different disciplines, but on combined projects it's one team from start to finish.

Process·July 15, 2026·5 min read

Seawall or Dredging First? South Florida Owner's Guide

New seawall, or dredge first? The order matters — for cost, for permits, and for how long your new wall lasts. Here's how a licensed South Florida contractor sequences the two.

Almost every waterfront owner in Palm Beach and Broward Counties eventually faces the same two-part question: the seawall is aging and the canal is shoaling — which do we fix first? The instinct is to treat them as separate projects on separate timelines. The right answer is usually to sequence them as one, and the order matters more than most owners realize.

As a marine contractor that handles both — Palm Beach Dredging is the dredging division of South Florida Seawall — we get this call constantly. Here's how we actually think about it.

The short answer

Dredge first, then replace the seawall — if both are needed within a few years of each other. Dredging clears the toe of the wall so the new seawall can be built to a proper design depth. Replacing the wall first, then dredging later, risks undermining the fresh wall or forcing an expensive second mobilization.

The exception: if your existing seawall is actively failing — tipping, cracking, or losing panels — the wall becomes the emergency and dredging follows behind it.

Why order matters: toe scour and design depth

Every seawall has a toe — the base of the wall that sits below the mudline. That toe carries a huge share of the wall's structural load. When sediment builds up in the canal, two things happen:

The effective toe depth shrinks, meaning the wall is designed for one bottom elevation but sits against a shallower one.
Prop wash from boats starts scouring sediment away right at the toe, creating a scour hole that undercuts the wall from below.

A wall built to a bottom that's already two feet high on sediment doesn't get the design embedment it needed. Dredging first restores the design bottom, and the new seawall's toe gets set to a real, engineered depth — not a temporary one that will vanish the first time someone dredges later.

The permitting savings of sequencing them together

Combined seawall + dredging projects share three expensive things:

Mobilization — one barge move, one crane setup, one crew mobilization instead of two.
Permit review — FDEP, USACE, LWDD, and municipal reviews can often be filed as a coordinated package rather than back-to-back applications months apart.
Access disruption — one closure of the dock or slip instead of two.

On a typical Boca Raton or Delray Beach residential job, sequencing the two together saves roughly $8,000–$15,000 in mobilization alone and cuts total on-water disruption by four to six weeks. If you already know both are coming, planning them as one project is almost always the cheaper path.

For the raw dredging numbers, see our 2026 canal dredging pricing guide. Seawall pricing is quoted by the linear foot and depends heavily on wall height, tieback design, and cap detail — we'll walk that separately during the survey.

When to replace the seawall first

There are real cases where the wall can't wait for the dredging schedule:

Visible tipping or rotation — the cap is no longer parallel to the water and the wall is leaning outward.
Panel separation or blown tiebacks — vertical cracks, gaps between panels, or bulging where a tieback has failed.
Active soil loss from the property side — sinkholes, voids, or pavement dropping behind the wall.
A recent named storm that opened a scour hole and destabilized the toe.

In those situations we build the wall first, protect the toe with temporary armoring or a scour apron, and come back for the dredging on the next window. Waiting to sequence perfectly isn't worth losing the wall.

When dredging can wait

Not every shoaled canal needs dredging on the same schedule as a seawall replacement. If you're seeing early signs — a few inches of lost depth, occasional touch at low tide — and the wall is sound, it's often fine to plan the dredging for a year or two out and let it drive the schedule. Use that window to file the LWDD, USACE, and FDEP paperwork so the project is permit-ready when the barge is available.

If you're not sure where you are on the shoaling curve, walk through the eight signs your canal needs dredging.

What a combined project looks like on the water

For a typical residential job in Boca Raton, Delray Beach, or Fort Lauderdale, here's the sequence we run:

Survey — bathymetric survey of the canal bottom plus condition survey of the existing wall.
Design + permits — new seawall design coordinated with the dredge cut, filed as one package.
Mobilize — barge, crane, and dewatering to site once.
Dredge — restore design bottom depths at the wall face and out into the fairway.
Demo + build — remove the old wall in sections, drive new sheet pile or install a new panel wall, place tiebacks, pour the cap.
Rip-rap / scour protection at the toe where warranted.
Demob — everything off the water in one move.

Total on-water time for a standard 100-foot residential wall with a small dredge cut is typically three to five weeks, versus running each as its own two-week mobilization months apart.

The bottom line

If you're facing both an aging seawall and a shoaling canal, don't quote them as separate projects with separate contractors. The order — dredge first when the wall can wait, wall first when it can't — and the coordinated permitting is where the real savings and the real longevity live.

Give us a call at 754-SEA-WALL and we'll come out, walk the wall, sound the bottom, and give you a straight read on what should happen first.

Frequently asked questions

Can you dredge right up against an existing seawall?: Yes, carefully. We keep the cut back a controlled distance from the toe and grade toward the fairway so we don't undermine the wall. If the wall is questionable we survey it before the dredge to know exactly what it can take.
How long does a new seawall last if the canal keeps shoaling?: A properly designed seawall lasts 40 to 60 years, but that assumes the design bottom stays close to what it was engineered for. Repeated shoaling and prop wash can accelerate toe scour and cut that life significantly — which is why sequencing dredging with seawall work matters.
Do combined projects need one permit or two?: Usually two applications — one for the dredging and one for the seawall — but they can be filed and reviewed together as a coordinated package. FDEP, USACE, LWDD, and your municipality all still get their own say; we file it as one project so the reviews run in parallel.
What if we only need part of the seawall replaced?: Partial wall replacements are common — often the corner sections or a run that took the worst prop-wash exposure. We match new panels to the existing wall and tie them in cleanly, and coordinate the dredge cut so the new sections get proper toe embedment.
Are you the same company as South Florida Seawall?: Palm Beach Dredging is the marine dredging division of South Florida Seawall. Same ownership, same crews, same equipment — we split the two brands because dredging and seawall construction are different disciplines, but on combined projects it's one team from start to finish.