I wanted to write a post to provide some background information about a few things about seawalls. You may hear the term, "bulkhead" or "retaining wall." These are pretty much interchangeable for the same thing, a wall to provide property protection. A seawall can be made of wood, corrugated vinyl sheeting or corrugated metal sheets. The way they are constructed is almost identical. All wood seawalls are the most common and least expensive choice.
Elizabeth and I are presently in the midst of our own wooden seawall construction project. We have a vacation property located in Mary Esther, FL. It is located between Fort Walton Beach and Navarre and directly on the Santa Rosa Sound.
Last September, our property was heavily damaged by Hurricane Sally. That storm destroyed 70% of all docks along the Sound. In our case, it caused total destruction to the dock, eroded twenty feet of hillside, as well as destroyed the beach fence. In fact, the storm was successful to the extent there was nothing to do in the way of storm clean up (*poof*). Gone!
Here is a photo gallery showing the property damage caused by Hurricane Sally. Several boats costing nearly half a million were thrown from their lifts and destroyed on the shoreline next to our home.
Seawall Construction: Our seawall has yet to be finished and we have been taking numerous photos documenting the construction process (see photo gallery below).
No heavy machinery.
Most may not realize it, and yet find it interesting, no heavy machinery has been used in the seawall construction. Marine contractors sink long pilings and wall boards using a water pump that jets water down through a pipe into a hole. Pilings sink down to the desired depth and workmen ensure all are properly level. When the pipe is removed from the hole, sand sinks around the pilings and wood boards are naturally cemented into place.
The water pump does dredge up sediments that temporarily stains the beach and the water. We have noticed this clears out overnight. In terms of noise, there is some hammering and sawing of lumber, but the process hasn't been overly loud. That said, with it being Spring Break and rental season, we have worked with renters on the work schedule.
Being on the marsh as Water's Edge is, it is all the more important the natural environment is left as undisturbed as possible. Where we expect equipment on our Mary Esther is the point at which we have to backfill behind the seawall with a Bobcat.
Currently, the marine construction company has the pilings and walers in place. Walers are the cross pieces of lumber that span the distance from piling to piling. The boards are doubled up creating a sturdy cross brace. The wall itself is made of vertical boards that get nailed into the walers. These boards are overlapped also creating a rigid surface.
What is left to do is filter cloth gets nailed to the landward side of the wall to prevent sand from leaching through boards. Tiebacks and anchors are then installed every so many feet to help keep the wall from falling from vertical, a common point of failure with seawalls. Finally, backfill levels out the hillside, sod will be laid and a beach fence will be constructed on top of the seawall with gates accessing stairs to the beach.
Should we have another storm like Hurricane Sally, the seawall should help to perform as a buffer by taking the energy out of waves that slap against it versus scouring and eroding the hillside revealing the concrete rip rap under the sod.
We hope this personal experience with seawalls will help to understand the process of building one and a little of what to expect in how they are constructed.