Seawalls are barriers designed to shield coastlines and property from flood and erosion. These robust structures come in different types: vertical, curved, and mound seawalls, depending on their size. These seawalls protect the coast, increase land stability, and serve unique purposes. However, the main drawbacks of seawalls are maintenance and building costs that range from $185-$2,000 or more.
Wonder thinking which materials are used to make seawalls, why do you need to build one, or how many years seawalls last? Discover our comprehensive guide - what are seawalls and get all the answers!
What are Seawalls?
Seawalls are wall-like robust structures built near coastlines to protect properties from severe wave action, tides, marine borers, and storm surges. These walls act as barriers, shielding coastal communities, infrastructure, and natural habitats from drawing the sea. They are vertical or near vertical shore-parallel structures.
The seawall's height almost covers the difference between the beach and mainland levels. It is generally built where a typical breakwater is either too large or not economical.
What are the Different Types of Seawalls?
There are three main types of seawalls: vertical, curved, and mound seawalls, which protect any shore coming from the sea. For more details, let’s check out below:
1. Vertical Seawalls (overall a great option)
Best for: Heavy wave areas (waves are greater than two meters).
Size: Typically 6-20 feet tall (depending on the tide and wave height).
Maintenance: It lasts almost 50+ years if properly maintained (patching any cracks, ensuring joints don’t separate, etc.).
Materials: Concrete, steel, and composite materials are used to build the wall.
These seawalls are built vertically (stick straight) to prevent wave energy from eroding the shoreline and protect properties. They are made of concrete or steel. They are a tried-and-true method of blocking waves and absorbing their full pressure. Seawall engineers suggest building vertical seawalls where the water is calm or the coastline is protected to avoid yearly repairs.
Key benefits:
Handle excessive wave force & reduce wall damage.
Great resistance and durability.
Easy to design & constructed type of seawall.
Divert wave energy away from the coast.
Some place stone piles in front of the wall to lessen wave energy.
2. Curved Seawalls (quality protection)
Best for: High-energy coasts to reduce wave impact on properties
Size: Similar to vertical seawalls but designed with curves or steps
Maintenance: It lasts almost 20-50 years if regularly inspected
Materials: Reinforced concrete, stone masonry, etc
Curved or stepped seawalls are designed to diversify wave energy and produce less turbulence in the water. Mainly, the structure mimics the shape of a wave. If you want to build a hotel or firm house close to the coast, the structure is the best choice to fight against natural disasters and the tide.
Key benefits:
Prevent waves from overtopping the wall.
Provide a habitat for coastal organisms.
Promote the exchange of sediment.
Help to mitigate the impacts of major storms.
3. Mound Seawalls (Quality Protection)
Best for: Low-energy environments and beach restoration projects.
Size: Low-profile, typically 3-6 feet tall.
Maintenance: 20-30 years (if built in a calm & low-wave areas)
Materials: Sand, gravel, riprap, etc.
Mound seawalls or ripraps are built with blocks and rocks to slow down an ocean wave before it hits the shore. Though the wall is less expensive, it might not stand strongly against high-energy shores. The walls are built in a curved shape to reduce wave energy on the coast.
Key benefits:
Minimize erosion and protect nearby land from low-profile wave impact.
Support ecosystems by providing shelter for fish and other marine species.
It is useful to protect beaches, riverbanks, and other coastal areas from erosion.
Prioritize aesthetics and environmental harmony.
How do you choose the right types of seawalls?
When choosing the right type of seawalls, consider several factors such as:
Wave energy and flow direction,
Water depth and currents,
Shoreline conditions,
Coastal geology,
Environmental factors, and
Your budget.
For example, vertical or curved seawalls are ideal for high-wave zones, whereas mound seawalls are ideal for low-energy areas. If you have a tight budget, you can go with vinyl or wood seawalls, but they may not last longer.
What are Seawalls Made of?
Seawalls are made of different materials, such as concrete, vinyl, steel, wood retaining, composite, boulders, etc., depending on the specific location needs and wave action. Below is a breakdown of the most common materials positive and negative effects that help you to choose the best:
Concrete: Highly durable and versatile material effective against strong erosion and waves. It lasts longer (50+ years with maintenance) compared to other materials. You have the flexibility to customize into different designs (i.e., curved, vertical, etc.).
Cons: Can crack without proper maintenance
Steel: It is used for seawalls sheet pile for exceptional strength and durability. The material is ideal for high-impact zones and heavy waves.
Cons: Vulnerable in saltwater environments & expensive enough for material and maintenance costs.
Vinyl (PVC): Lightweight synthetic material, easy to install, resistant to corrosion, and affordable like concrete.
Cons: Limited structural strength for high-impact zones.
Stone or riprap: Natural stones or boulders are environmentally friendly and excellent for erosion control.
Cons: Less effective against heavy waves & requires periodic replenishment.
Wood: Pressure-treated timber is used for small-scale or temporary seawalls.
Cons: Prone to rot and insect damage in water.
Sounds impressive! Curious about what seawalls do apart from protecting properties or the pros and cons of seawalls?
Now, let’s check out the benefits of seawalls in the next section!
What is the Purpose of Seawalls?
The key purpose of sea walls is to mitigate the effects of water and wave action, preserving the land and infrastructure. Other benefits are mentioned below:
Coastal erosion prevention (protect properties from frequent storms, prevent coastal lands from washing away, etc.).
Flood protection (Urban seawalls like Miami and New Orleans protect from flooding during high tides, hurricanes, etc.).
Wave energy management (absorb or deflect wave energy, minimize damage, etc.).
Flexibility in design.
Environmental friendly.
Low maintenance.
Adaptive to climate change, and more.
What are the Advantages of Seawalls?
The advantages of seawalls are as follows:
Versatile: Seawalls are designed in different styles (vertical, curved, riprap, etc) as per environmental requirements.
Space efficiency: Seawalls require less land compared to other structures like dunes or berms.
Eye-catching: These structures are made with different materials that enhance the visual appeal of coastal properties.
Property value preservation: These structures protect property against erosion and flooding.
Long-term solution: Seawalls made of concrete, steel, rock, or other materials that last decades with proper maintenance.
Withstand extreme water levels: Protects property and areas from erosion and floods.
What are the Disadvantages of Seawalls?
The disadvantages of seawalls are as follows:
Limited lifespan: Some seawalls are durable, while others, like wood or vinyl, might not last long.
High construction costs: Seawalls are built with durable materials ranging from $180-$2,000 per linear foot or more.
Maintenance requirements: Concrete seawalls last long and require minimal maintenance. However, wood or vinyl ones require regular repairs.
How Much Do Seawalls Cost?
As per seawall professional engineers, the seawalls cost $65-$2,000 per linear foot, depending on the waterway depth, locations, and other factors. The average residential project will be $15,000 to $60,000. If you want to build a seawall in a commercial or high-erosion zone, it might cost around $700 to $2,000 per linear foot.
Here, we’ve highlighted 5 key factors that affect seawall costs:
1. Materials
Depending on seawall materials, soil type, and water characteristics where it is built, the cost per linear foot varies:
Seawall Type | Cost per linear foot |
Vinyl | $200-$600 |
Steel | $250-$700 |
Concrete | $220-$850 |
Wood | $110-$450 |
Riprap | $70-$210 |
2. Size
The total price of seawalls varied on the linear feet and wall size. Some seawalls are built in a portion of the property, but some are built encircling the entire yard or at least the side against the body of water. However, engineers build from four or five feet high to 15-20 or more depending on soil type and water depth against the property.
For example, a 150-foot concrete seawall might cost $20,000–$77,000, whereas a 150-foot wood seawall might cost $15,000–$44,000.
*Note: Consult your selected seawall repair and building company for more in-depth details.
3. Custom Seawalls
Sometimes property owners demand custom seawall solutions that might cost anywhere between $100 to $800 depending on,
Linear foot
Length
Complex or commercial projects
Shoreline conditions, and
Location.
On average, the seawall installation cost around $25,000 or more.
4. Labor
Calculating the cost of seawall contractors and engineers for larger projects like this is quite challenging. In these cases, experts suggest calculating the hourly rate between $40 and $100 per hour. However, if heavy equipment like cranes or bulldozers is required, the price will be up to $300 or more an hour. So, contact a local seawall repair and building professional in Southeast Florida for an in-depth discussion.
5. Preparation
Building a seawall requires planning and more preparation. Suppose a seawall is damaged, and soil can drain into the water and destroy the foundation. Some pricing factors are:
Keynotes | Work Details | Costs |
Site survey | Soil condition testing and its density, measuring the distance between the property and the seawall building location, monitoring high and low tide levels, etc. | $800-$5,000 or more |
Necessary permits from the local Government | Several inspections of projects before the permit. | $150-$2,500 or more |
Environmental impact assessment | Inspection of coastal areas effects (elimination of tidal habitats & increase erosion of other beach areas) when seawall constructed. | 2,000 to $12,500 or more |
Seawall design work | Need to hire structural engineers with soil mechanics and conditions knowledge. | Depends on individual skills |
As per Statista, the US different states are expected to pay over $400bn on seawalls up to 2040. So, to get detailed cost ideas, you can consult with a trusted and renowned seawall repair service provider to get,
Plan materials logistics
Water blockage
Emergency protocols development, and many more.
DIY Building a Seawall vs. Hiring a Professional
Planning to build a seawall utilizing the DIY hacks? It might not be a wise decision to make a seawall by yourself; you might end up with a poorly constructed and dangerous seawall. So, try to consult with a reputable seawall building and repair company. For example, Total Seawall Repair, where you get high-quality and guaranteed seawall repair services with certified experts, and so on.
How Long Do Seawalls Last?
The lifespan of a seawall is 30-40 years or more, depending on different factors, such as materials, environmental conditions, maintenance, and construction quality. How long do concrete seawalls last or other materials? Let’s take a look at below:
1. Lifespan by materials
Concrete seawalls: Last 40-50 years for its highly durable nature.
Vinyl or composite seawalls: The lifespan of these seawalls is 25-40 years. Resistant to corrosion and rot works well in brackish and saltwater environments.
Steel seawalls: The lifespan is 25-50 years. Strong and ideal for heavy-duty applications.
Riprap (stone) seawalls: Last 50+ years for its durable and long-lasting shoreline protection shield.
Sheet pile: It’ll last for 50 years or more for its high corrosion resistance and durability.
Wooden seawall: It’ll last between 10-30 years due to its susceptibility to rot and damage from exposure to water and weather elements.
2. Seawall longevity factors
Environmental conditions: Saltwater exposure increases damage risks for steel and concrete seawalls. Meanwhile, strong wave action or high tide areas can accelerate wear and tear.
Maintenance: The lack of proper inspections and minor repairs increases damage risks.
Construction quality: Professional installation ensures better structural integrity and increases lifespan.
Usage and load: Areas with minimal humans or heavy waves tend to have longer-lasting structures.
Conclusion
In the conclusion of this article: what are seawalls? You’ve already acknowledged that these structures are vital in safeguarding coastal areas, infrastructure, and communities. Like any other engineering structure, seawalls come with different challenges, like maintenance needs, costs, and more. So, it’s wise to consult with a renowned seawall repair and construction company to make informed decisions tailored to specific coastal needs.
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