Seawall construction by Gibson Marine at Sand Key Park

How to Tell If Your Seawall is Damaged

A popular waterfront restaurant on the North Shore of Boston was forced to evacuate and is now closed until further notice after a seawall underneath it partially collapsed.

One of the owners of Mission on the Bay in Swampscott told Boston 25 News about 60 people were eating lunch inside when it happened around 1:45 p.m.

Swampscott’s Department of Public Works believes the collapse was likely caused by erosion.

A well-built seawall is essential to any waterfront property and if your seawall fails, it can be devastating to the homeowner but also to the houses nearby.

Seawall erosion in restaurant in Massachussetts.
Seawall erosion in restaurant in Massachussetts.

Seawalls are a vital feature of coastal communities worldwide. They offer protection against storms and tides, allowing people to build homes and businesses along the shoreline. However, seawalls are not indestructible and require proper maintenance to keep them functioning correctly. Erosion is a significant problem that can weaken and eventually collapse a seawall. As such, it is crucial to understand why it happens, why maintenance is important, how to identify risks, and what kind of professionals can fix it.

Seawall erosion happens when waves, tides, and storms batter the wall over time, leading to the loss of soil and sediment supporting the structure. As a result, the wall becomes weaker and more prone to failure. Additionally, factors like climate change, rising sea levels, and an increase in storm frequency can exacerbate erosion problems.

Maintenance and seawall repair is critical to preventing seawall erosion. Regular inspections can help identify issues before they become significant problems. Repairing small cracks and other damages immediately can prevent water from infiltrating the wall and causing further damage. Additionally, regular cleaning of the wall’s surface can remove debris that can cause damage or harbor organisms that can eat away at the structure.

Identifying risks is an important step in preventing seawall erosion

Signs of erosion can include sinkholes near the base of the wall, exposed rebar or steel, and cracks or bulges in the wall’s surface. These signs should not be ignored, and immediate action should be taken to prevent further damage. Additionally, homeowners and businesses should be aware of the local weather and tides to understand when the seawall may be at risk of damage.

A recent case of wall collapse in South Florida have highlighted the importance of proper maintenance. In 2021, the Champlain Towers South condominium building collapsed, leading to the loss of over 90 lives. One contributing factor to the collapse was the building’s wall, which had not been adequately maintained. A report from 2018 showed that long-term degradation of reinforced concrete structural support in the basement-level parking garage under the pool deck, due to water penetration and corrosion of the reinforcing steel is likely the cause of the tragedy.

Marine construction contractors are professionals who can fix seawall erosion problems. They can repair cracks, replace damaged sections, and perform regular maintenance tasks to prevent erosion. Engineers can assess the seawall’s stability and design repairs or reinforcements to prevent further damage. Geotechnical experts can evaluate the soil and sediment beneath the wall to identify potential problems and recommend solutions.

Erosion can weaken and eventually collapse a seawall, leaving homes and businesses vulnerable to damage from storms and tides. Regular maintenance, risk identification, and professional repairs can prevent erosion and ensure the seawall’s stability. It is essential to prioritize seawall maintenance to protect coastal communities and prevent catastrophic failures.

Tropical Storm destroyed seawall in Wilbur by the Sea, FL

Our friends at Gibson Marine put together a list of five signs to keep an eye out for signs of seawall damage. This list can help you keep your seawall properly maintained and help prevent seawall failure.

Five Signs Your Seawall Needs Repaired or Replaced

Regularly inspecting your seawall for signs of damage can help you determine if your seawall may be in need of repairs. While performing these regular inspections, answer the following questions:

1. Cracks or Small Chunks Broken Off of the Seawall Cap

If you see cracks or small chunks missing from the cap, this can mean the rebar is exposed. This exposure can lead to corrosion of the rebar, weakening the seawall, and potentially causing it to fail.

2. Visible Rust Stains on the Seawall

Visible rust stains are another sign of possible corrosion. It is important to find out where the rust stains are coming from. Sometimes the source can be easy to pinpoint, such as it coming from an exposed metal railing or decorative feature. Other times, it may appear to be seeping through cracks in the seawall’s surface.

3. Large or Widening Gaps Between Seawall Slabs

If you see a gap between seawall slabs that is significantly larger than the other gaps between slabs, or the gaps appear to be widening in general, this could be a sign that the joints have weakened or broken.

4. Seawall Slab Damage is the Leading Cause of Sudden Seawall Failure

Seawall slabs are under constant stress and pressure. A pressure imbalance can lead to a slab cracking, bowing, leaning, or becoming misaligned. And if the slab is not repaired or replaced, and the pressure balance restored, the slab(s) can buckle resulting in a partial or complete sudden seawall failure.

5. Soil Settling or Holes in the Ground are Signs of a Seawall Pressure Imbalance

Soil settling or holes in the ground along or near your seawall are signs of erosion. Erosion is another common cause of a pressure imbalance, that can lead to slab damage and potential seawall failure.

The video below gives us a peek at the engineering and construction work that goes into building a stable seawall, capable of withstanding hurricanes, tropical storms, and the foot traffic of over one million park visitors each year.

Max Francisco