Owning a home on waterfront property has its benefits, with immediate access to the water and beautiful views, but it also has its drawbacks. As the water laps at your property line, it can erode away and destroy your land and put your home at risk of damage. Here are instructions to help you install a new three-foot seawall on your property to help prevent this from happening.
Plan Your Seawall Construction
Once you have obtained any required permits and approvals from your area to build a seawall on your property, you can begin planning where you want to install it. It is also important to plan when you can do the construction work if your home is on a tidal ocean coastline. This will help you to do the work while the water is at its lowest level during low tide. Low tides occur every 12 hours and 50 minutes, so determine when this occurs on your waterline and make plans to do the work while the water is away from your seawall site. If necessary, you can space out the construction of your seawall over several days, during each day's low tide.
Prepare Your Supplies
The best materials to install a seawall yourself are 3-inch-wide steel pipes and two-by-ten lengths of pressure-treated lumber. To build a three-foot tall fence you will need six-foot long pipes, as half the length of each pipe will need to be buried in the ground. For each steel pipe post, you will need six lengths of threaded 1/2-inch wide rebar cut to 12-inch long lengths.
Bend each length of threaded rebar in a U-shape to fit around the outside of the pipe. Then, beginning at the top of each six-foot long steel post measure and weld a U-shape threaded rebar at 3 inches, 7 inches, 13 inches, 17 inches, 23 inches, and 27 inches down the length of pipe. Make sure all the ends of each U-shape point in the same direction. You will use these rebar ends to mount and secure your pressure-treated boards for your seawall.
Install the Post Holes
Mark and dig post holes three feet deep every eight feet along your seawall line. Set a steel post into a hole with the threaded rebar pointing toward the water. Fill the hole with pre-mixed quick-setting concrete. Use a level to make sure you position the post vertically before it sets. Repeat this with the remaining seawall posts.
As you begin this step, make sure you are at the beginning of a low tide, so water will be away from your post holes for as long as possible for the concrete to set. If the tide begins to come back in and you don't have time to finish installing all the post holes, put the work off until the next day's low tide to complete it.
Install the Pressure-Lumber
Using a 1/2-inch drill bit, drill two holes on each end of pressure-treated lumber. Space the holes 4 inches apart and 2 inches from the end of the board. Lining the holes up to the threaded rebar, mount the boards onto the steel posts to construct your seawall. Thread metal washers and nuts onto each threaded length of rebar protruding from the treated lumber, which will secure the seawall onto the posts.
Backfill the New Seawall
Now you have completed your seawall, you can backfill soil behind the wall. This will help level off your property along the waterline and make the shore more attractive.
Fill the bottom of the seawall with a layer of gravel or crushed rock several inches thick. This will allow water runoff to drain from the shoreline into the water and prevent erosion. Then, Cover the gravel and crushed rocks with a layer of sand, then topped with topsoil for you to landscape to your preference.
It's important to know that it will require periodic seawall repairs and maintenance, but this should help keep your property in order.