How to Build and Install a Seawall
With decades of experience, Everlast Synthetic Products has been providing superior Synthetic Sheet Piling for the construction of state of the art seawalls. Our seawall manufacturing and engineering expertise are second to none.
As a helpful resource, we’ve created this general “How to Build and Install a Seawall” guide as an overview of the process involved. For more detailed support, you are always free to contact us with any questions!
1. Research Local Rules and Regulations
Be sure to research any local permits, special codes or regulations that you may need to follow or apply for. This is a crucial step for any commercial or residential project. This ensures that you’ll be able to complete your project successfully without interfering with the environment in and out of the water.
Whether or not you need permits or have regulations to follow varies based on location. Some require USACOE (army corp) permits, some Department of National Resources (DNR), some just local permitting. Each state, county or even lake can be different. A good start is the Wikipedia page on Environmental Agencies by State, but let us know if you need any help!
2. Measure Twice, Drive Once
Before you get started, you’ll need to know the quantity and types of seawall materials you’ll need. Seawalls can vary greatly in cost depending on what materials are used. The type of materials selected typically takes into account the demands of the environment. A small canal or golf lake can make use of lighter, shorter products, whereas oceanfront requires stronger, more deeply-driven sheets.
The easiest way to scope out your project needs also happens to be free! You can talk to one of our experienced seawall engineers who can produce a free estimate.
3. Set Up Your Drive Guide
A drive guide is a horizontal typically wood structure to set up to help keep your sheets in alignment with each other during the sheet driving process. Assembling a drive guide before you begin installation of a seawall provides you with a precise wall position during installation. The drive guide is crucial to ensure a straight and firmly placed wall. Drive guides are essential; do not attempt to drive sheets along just a string line.
The first step to setting up your drive guide is to install temporary posts. Run a string line where the wall will stand for proper pole placement. We recommend using 4” x 4” posts. Again, please note that the string line is used for pole placement to set up a drive guide, NOT for the wall itself.
The drive guide should have an approximate size of four to six feet by six feet, and can become a piece of the permanent structure for a wood capped wall. Position your drive guide to the temporary posts by tack nailing it, screwing it or securing it with c clamps.
4. Drive Your Sheets
When using the Z panel sheets (as opposed to full box sheets), sheets are often “threaded,” or driven side by side in pairs. This speeds up install time and helps your sheets stay in alignment during the driving process. The name “Z panel” refers to the shape of the sheet’s profile.
Before driving, be sure each pair of sheets is lined up horizontally and vertically. It is critical that you get the first pair of sheets you install straight and plumb, so the rest of the wall can follow suit. If you encounter tough soils you do have the flexibility of going from one single sheet to the next.
We recommend starting with the male piece so that soil and debris can escape via the female. After reaching your desired embedment point, place a lag screw in the flange on your leading sheet of the pair.
Though with a “don’t try this at home” claimer, check out the below video of our vinyl sheet pile being driven by a backhoe bucket. Imagine the forces involved in that process and you’ll start to get a sense of how strong our sheet pile really is!
In this 2nd example, the Army Corps of Engineers trusts ESP vinyl sheet piling for a project in North Carolina. Here they use a vibratory hammer for install:
5. Secure Waler Boards
Continue building your seawall by installing front or back walers utilizing carriage bolts or all-thread (AT) rods to secure. Carriage bolts (or AT) should be used approximately every 2’ –3’ between tie rod placement.
ESP inventories a large supply of both hot dipped galvanized and stainless steel fasteners, tie rods, carriage bolts, nuts, washers, and all thread rod.
For simplicity and reliability, we produce a stainless steel install set with downloadable directions:
When your walers are secure to the wall, the seawall should look like this:
Tie rods should be secured through the front and the back of your waler. Once through your waler, the tie rod should be attached to a deadman behind the wall as seen below.
This area will then be backfilled to cover the tie rods and deadman.
Generally, walers are wood, and are put in place during the creation of your drive guide. Our friends at PileBuck have a great resource explaining the importance of walers. Walers typically become a permanent feature of the seawall.. However, walls that don’t have a wooden top cap can use steel or another strong source to make up the drive guide.
6. Complete Your Installation
Finish off your wall with the installation of the top cap board. Generally, your top cap board will be a pressure treated 2” x 12” board or deck that sits perpendicular to the walers.
Whether you’re a professional contractor, ambitious do-it-yourself, neighborhood or governmental entity, or a real estate owner in need of erosion protection, ESP is here to help with all your seawall construction and installation needs. You can contact us or even easily submit a request a free estimate.