
Seawalls
Seawalls must withstand some of the most brutal conditions of any marine
structures built today. Cracking, bowing, or erosion of the ground behind
the wall can be signs of trouble. Heavy loads due to high levels of ground
water, violent storms, and marine borers are just a few of the hazards to
consider when choosing which contractor and material to use to protect
your waterfront property. Several of the most commonly used seawall
materials that can protect your most valuable investment are available
through Duncan Seawall and are described below:
Concrete Seawalls
Duncan Seawall is the area’s leader in installing the most durable concrete pre-cast seawalls.
Our concrete sheet panels are manufactured off-site by a professional concrete fabricator with
on-staff engineers to ensure that each panel is constructed using the highest level of quality concrete
consistency. The panels are 8” thick, include 5,000 P.S.I. concrete and continuous steel rebar
throughout, and are properly cured for approximately six weeks. These specifications provide the
strength and stability needed in a superior concrete panel seawall.
After installing the concrete panels, Duncan Seawall supports the seawall with a steel reinforced
concrete cap and tieback system. Each tieback rod consists of a ¾” diameter hot dipped galvanized
threaded rod with a 6” x 6” plate bolted to each end, securing the cap to an independent concrete
base buried in the yard. Steel rods are not heated or bent in the field due to the reduction of structural
integrity induced in the tieback rod.
Lastly, the wall is finished with a 20” x 22” wide 5,000 P.S.I. concrete cap that is long lasting,
aesthetically pleasing, and an added value to your waterfront property.
Corrugated Seawalls
In instances where a concrete seawall is not a viable option for the customer, Duncan Seawall
offers a variety of corrugated panel alternatives that can be installed for both heavy and light
duty applications.
Steel
Steel sheet panels are a long lasting, interlocking system that creates an extremely strong continuous
wall (similar to concrete). Steel panels are primarily used when the exposed wall height is large or
when other panels cannot be jetted or driven into the subsurface. In some areas, a rock or clay layer
may exist below the sand table making steel panels the best solution. Steel sheet panel installation
requires heavy equipment, which Duncan Seawall owns to make the installation the perfect solution
when specified.
Aluminum
One of the most important design criteria to consider when choosing a sheet panel is the strength
to weight ratio. This will dictate the strength of panel needed to support the load behind the wall.
Aluminum is an excellent material for use when an alternative material, such as vinyl or composite,
is not strong enough to be driven into the ground due to tree roots, rock, or clay strata being present
under the sand table. Aluminum has the strength to be driven through most obstructions while
remaining light enough to install without heavy equipment.
Vinyl
Whether you are installing a retaining wall on a lake or reinforcing your concrete seawall that has
a swimming pool nearby, Duncan Seawall has the vinyl product that will work best for you. These
panels can be installed using little or no heavy equipment, which is an excellent choice when there
are tight conditions or limited access.
Composite
A composite seawall is manufactured using a pultrusion process, which creates fiber reinforced
polymer profiles of extraordinary strength and resilience. These panels are designed and
manufactured to provide an alternative solution to concrete, steel, aluminum, or vinyl and are
available in a variety of colors, further enhancing the look of your waterfront. Composite seawalls
often require little or no heavy equipment to install.
Due to the numerous materials available, Duncan Seawall will guide you through your options
when making your seawall investment.