When you live on a barrier island, just keeping your little
piece of real estate from washing away is a constant struggle.
Fred Sprinkle, a foundation and excavation contractor on
Dauphin Island, Ala., frequently uses vinyl sheet pilings to
keep the ground beneath his clients' homes from ending up in
the Gulf of Mexico.
His employees — who spend as much time in the water as
they do on land, and dress accordingly — start one of
their vinyl seawalls by building a frame of pressure-treated
wood pilings and dimensional lumber (1). The lumber and pilings
are CCA-treated; newer pressure-treating formulas don't hold up
as well in saltwater and aren't as resistant to marine-boring
Once the frame is assembled, the crew ties it to dry ground
with stainless-steel threaded rods and earth anchors (2).
Next, workers use a gas-powered pump (3) to wash holes in the
sea floor for the 12-inch-wide piles. The pump sends water
first through a 2-inch hose and then through a 11/2-inch steel
pipe (4); the transition from a larger to a smaller diameter
increases head pressure. The pipe's weight makes controlling
and directing the stream of water easier.
Once the holes are made, the crew pushes the 12-foot-long sheet
pilings in; some piles go easy, and others require persuasion
with a sledge or a small pneumatic jackhammer (5). All have
mating edges that lock them together (6). They're nailed to the
wood frame at the top and at the water line.
The walls' integrity depends on how deep the pilings are placed
in the sand. The day I visited, workers were replacing a poorly
built wall with one that went about twice as deep.
Unscrupulous contractors often use shorter pilings to save time
and money, but occasionally even competent installers face an
obstacle that makes it impossible to drive the pilings to their
When Sprinkle's employees run into this problem, they try to
remove the obstacle any way they can. Sometimes they keep
enlarging the hole till they can pull the object out by hand;
other times they lug it out with a chain connected to their
excavator or backhoe (7). Only as a last resort do they cut the
Once all the piles are installed, the area is backfilled with
sand and the wall is finished with a pressure-treated
This kind of work may sound like a day at the beach, but crew
members told me cuts and puncture wounds on hands and feet
— plus nasty sunburns — are common. They also said
that despite the large retrieval magnet kept permanently in the
truck, they lose hammers and other hand tools regularly.