Polyurethane vs. Traditional Seawall Repair - Which Method Lasts Longer

A seawall is one of the most important structures protecting a waterfront property. It holds back soil, prevents erosion, stabilizes the shoreline, and keeps your yard, pool, or dock safe from tidal forces and storm surge. But like any structure exposed to water, pressure, and weather, seawalls eventually show signs of wear. When voids, sinkholes, or cracks appear, the question becomes: What is the best way to fix it and which repair method will last the longest?

For many years, homeowners only had a few traditional options: concrete patching, riprap, or costly full replacement. Today, polyurethane seawall repair has transformed the industry by offering a faster, cleaner, and longer-lasting solution.

Below, we compare polyurethane injections with traditional seawall repair methods so you can make an informed decision about protecting your shoreline investment.

Understanding the Cause of Seawall Failure

Before comparing repair methods, it helps to understand why seawalls fail in the first place. Most problems begin behind the wall and not on the water side.

Common causes include:

• Voids forming behind the seawall

• Soil erosion and washout from tides, rainfall, or irrigation

• Hydrostatic pressure pushing against the wall

• Cracks or open joints where water escapes

• Aging concrete or deteriorating metal

• Poor drainage or outdated weep holes

Once soil starts escaping through cracks or gaps, the area behind the seawall becomes unstable. Sinkholes form in the yard, slabs settle, and eventually the seawall may bow or crack. This is why the method you choose matters so much. The goal isn’t just to fix what you see but also to stabilize the soil and prevent future erosion.

Traditional Seawall Repair Methods

Traditional methods typically fall into three categories: concrete patching, riprap, and full replacement. Each has limitations that can affect how long the repair lasts.

Concrete Patching

This method involves applying new concrete to cracked or deteriorating sections of the seawall. Concrete patching is simple and relatively inexpensive, making it a good solution for cosmetic repairs. However, it doesn’t address soil loss behind the wall, it does not stop erosion, and cracks often return. In other words, concrete patching only treats the symptoms and not the root cause.

Riprap (Rock Placement)

Riprap installs large stones along the water side of the seawall to break waves and reduce impact. It helps reduce wave energy and improves shoreline protection. The downside to this method is not addressing the voids behind the seawall, not stopping soil from washing out, and settling issues from heavy rock. Riprap can also be difficult to install in tight canals or residential areas. It’s a helpful supplement but not a true repair solution.

Seawall Replacement

When damage is severe, complete removal and reconstruction may be required. With this method, you get a brand new seawall, which may be necessary for total failure situations. However, a full replacement can be extremely expensive, disruptive to your property, and require a long installation timeline. Plus, the seawall can remain vulnerable if backfill washes out in the future.

Polyurethane Seawall Repair: The Modern, Long-Lasting Solution

Polyurethane seawall repair uses a high strength, expanding foam injected through small ports behind the seawall. As the foam expands, it fills voids, compacts soil, seals cracks, stops water flow, and stabilizes the wall from behind. It’s essentially a one-and-done solution!

Unlike traditional repair methods, polyurethane addresses the root cause of failure: soil erosion.

The advantages include:

• It Stops Soil Loss at the Source. Traditional methods focus on the surface. Polyurethane stabilizes the soil underground, preventing future washout.

• It Seals Cracks and Gaps. Expanding foam fills even the smallest cracks where water escapes, removing entry points for erosion.

• It Prevents Sinkholes and Settlement. By strengthening the ground behind the seawall, it restores soil density and prevents future sinking.

• It’s Waterproof and Long-Lasting. Unlike concrete patching that can wear away, polyurethane doesn’t break down in water.

• Fast Installation, Long-Term Stability. Most injections take only a few hours and homeowners can typically use their yard the same day.

Traditional methods either fail to treat underlying problems or require major reconstruction. Polyurethane provides structural stabilization and erosion prevention, which makes it a superior long-term solution.

Which Method Should You Choose?

Polyurethane is ideal when:

• Sinkholes or voids appear behind the seawall

• Backfill is washing out

• The wall is still structurally sound

• Cracks appear but the wall isn’t near collapse

• You want a non-invasive, long-lasting repair

Traditional methods may be needed only when:

• The seawall is severely cracked or broken

• Structural panels have collapsed

• Tiebacks have failed

In many cases, polyurethane can prevent major failure and help homeowners avoid expensive replacement.

Polyurethane Offers the Best Long-Term Protection

Traditional seawall repair methods can help temporarily, but they rarely address the real cause of failure. Polyurethane seawall repair stabilizes the soil, stops erosion, and strengthens the seawall from behind, making it the longest-lasting and most efficient option for most waterfront homes.

If you're noticing sinkholes, settling soil, cracks, or water loss behind your seawall, now is the time to act. Foremost Foundations & Construction specializes in polyurethane seawall repair and can help protect your property with a solution that lasts. Contact us today at 601-405-1052 to schedule an inspection.