Bulkhead vs. Seawall — What's the Difference?

Ask three marine contractors in Jacksonville what the difference is between a bulkhead and a seawall and you will get three answers, at least one of which will be “there isn’t one.”

That is close to true in practice. It is not quite true in engineering, and the difference is worth understanding because it affects what your wall actually needs.

The textbook distinction

A bulkhead is a soil-retaining structure. Its job is to hold ground back — to keep your yard from sliding into the water and to give you a defined edge. The design is governed by lateral earth pressure: the weight and behaviour of the soil behind it, plus any surcharge load from what is built on top of that soil.

A seawall is a wave-resisting structure. Its job is to take the energy out of water before the water takes the land. The design is governed by wave loading: the force of waves hitting the structure, water levels during storms, and the energy the wall reflects back into the water.

That is the distinction. One is about the dirt behind it; the other is about the water in front of it.

Why nobody in Florida maintains it

Because nearly every vertical wall on a developed Florida shoreline does both jobs. It retains soil and it takes wave energy. The question is never “which of these two things is it” — it is which force governs the design, and that is a matter of degree.

A wall on a sheltered tidal creek with minimal fetch is overwhelmingly a soil-retention problem. Call it a bulkhead.

A wall facing a mile of open river, taking wind-driven waves and channel wake, is overwhelmingly a wave-resistance problem that also happens to hold soil back. Call it a seawall.

Most First Coast properties sit somewhere between those two, which is why the words blur together and why both are used for the same structure.

What actually changes in the design

This is the part that matters, and it is why we keep the two apart on this site even though the words do not stay apart in conversation.

	Soil-retention governs	Wave resistance governs
Primary load	Lateral earth pressure and surcharge	Wave impact, hydrostatic and water levels
Toe protection	May not be needed on sheltered water	Normally essential — the wall scours its own foundation
Cap elevation	Set by grade and finished edge	Set by freeboard against overtopping
Section selection	Driven by retained height and soils	Driven by wave loading, which is often heavier
Embedment	Depth for soil load	Depth for soil load plus allowance for scour

Toe protection is the big one

A vertical wall standing in wave energy reflects that energy downward and back into the water at its own base. The reflected energy excavates the seabed at the toe, removing the embedment the wall depends on.

The wall undermines itself. Continuously, invisibly, from day one.

Toe protection — armour stone or an equivalent detail — absorbs that energy before it can do the digging. On exposed shoreline it is part of the design, not an optional extra. On a genuinely sheltered creek frontage it may not be needed at all.

If you are comparing estimates and one of them has no toe protection on an exposed site, that is the question to ask before you compare the totals.

So which one do you have?

The useful question is not what to call it. It is:

How much open water is in front of you? Fetch builds waves. More fetch means wave loading matters more.
How much boat wake do you get? On the Intracoastal and the main channels, wake is often the governing load, continuously.
How much soil are you retaining, and what is on top of it? A lawn is one thing; a driveway or pool deck is a surcharge load that changes the structural design.
What does the wall’s toe look like at low water? Scour there tells you wave energy is winning regardless of what anyone called the structure.

Those four answers determine what your wall needs. The vocabulary does not.

Where to go next on this site

We keep bulkhead and seawall content separate because the design drivers genuinely differ — not because we think you should care about the terminology.

Bulkheads — soil retention. Construction, repair, replacement, and the three materials: concrete, vinyl, wood.
Seawalls — wave resistance. Construction, repair, replacement, plus the three specialist repairs: chemical grout injection, concrete cap and wall repair and void filling and soil stabilization.

And if your lawn is sinking near the wall, the terminology is irrelevant and the timing is not — read void filling and soil stabilization, because that problem compounds.

Call (904) 327-3931 or request a free estimate. We will tell you which problem you have.

Frequently asked questions

Which word should I use when I call a contractor?

Either. Any marine contractor on the First Coast will understand you, and we answer to both. What matters far more is describing what you are seeing — a lawn that is sinking, a wall that is leaning, water weeping through joints — because the symptom tells us more than the terminology does.

Does my permit say bulkhead or seawall?

Permitting agencies have their own terminology and definitions, which may not match either common usage or this article. What the agencies care about is what you are proposing to build and where, not what you call it. Confirm current requirements and terminology with the reviewing agency for your site.

Is one more expensive than the other?

A wall designed for wave exposure generally costs more than one designed only to retain soil, because it needs toe protection, a heavier section, and more freeboard. That is a cost difference driven by the conditions, not by the label. The same structure does not get cheaper by calling it a bulkhead.

Can a structure be both?

Most are, in practice. Nearly every vertical wall on a developed Florida shoreline both retains soil and takes some wave energy. The distinction is about which force governs the design, not about two entirely separate categories.

Published October 4, 2026 · Last reviewed October 2026 by Barefoot Marine Construction. Agency requirements change — confirm current requirements with the reviewing agency before planning work.

Bulkhead vs. Seawall: What Is the Actual Difference?