Bulkheads are often a necessity when living near the water, whether it is the ocean, a lake or a river. They prevent erosion of the shoreline, keeping your valuable soil in place, and provide a distinct separation between the water and the land. Bulkhead materials can also be used on land as retaining walls, to keep soil from traveling down inclines, or for water control, including protection against flooding or to divert water into a predefined area.
Traditional bulkhead materials include wood timbers, treated lumber used for sheeting and steel sheet pilings. These materials work reasonably well and are cost-effective, but the wood can easily be damaged by the water and rot away, while the steel suffers from corrosion and electrochemical reactions. Today, there are many advanced bulkhead materials on the market that are less prone to water and corrosion damage, including vinyl, composite and aluminum products.
Here is an overview of the bulkhead materials that are commonly available today:
#1 Wood Pilings
Wood pilings are large wood timbers that are driven into the ground tip-first, or with the narrow end pointed down. They can be used alone, placed side by side to control erosion, or in combination with tongue and groove lumber or other sheeting materials, with the pilings spaced evenly and the sheeting filling in the gaps between them. Wood pilings are available in both natural versions and treated versions, with differing chemical formulas and concentrations for fresh or salt water exposure. They are also available in a range of lengths and diameters, with either a natural tapered diameter or a milled universal diameter. Other types of milled timbers are available as well, including timbers with square or rectangular cross sections.
#2 Treated Lumber Sheeting
Between wood pilings, sheeting is often used hold back the soil and keep it separated from the water. Traditionally, the sheeting has been treated wood boards, in common sizes such as 2 by 10 inches, with a tongue machined in the center of one edge and a matching groove on the other. This allows multiple boards to lock together to create a strong surface, supporting the weight of the soil between the pilings. The boards are available with chemical treatments rated for either saltwater or freshwater exposure, and they come in assorted lengths. Treated lumber will resist water damage, fungal damage and rot for many years, but may be prohibited in some areas due to the chemicals used in the treatment process.
#3 Steel Sheet Pilings
Steel sheet pilings are large vertical sections of interlocking steel panels, with a ridged design that lends them strength and increases their rigidity. They are often used alone, or in conjunction with vertical wood or composite pilings, and they are driven directly into the ground. Once the panels are installed, interlocked and capped, they provide a strong barrier against erosion and wave action, but they are prone to corrosion, electrochemical reactions, and physical damage that can weaken them over time. They are also heavy, and relatively expensive compared to other materials.
#4 Vinyl Sheet Pilings
Vinyl sheet pilings were designed as an alternative to steel sheet pilings, which have a relatively short lifespan due to corrosion, especially in saltwater marine environments. They are larger interlocking vertical sheets, with large vertical ridges or channels that add extra strength and rigidity. They are driven into the ground similar to steel sheet pilings, and can be capped to enhance their strength. When installed correctly, they are as strong or stronger than steel pilings, without the corrosion problems or electrochemical reactions common with steel. They are available in a variety of finishes, and are resistant to damage from the weather, the waves or the ultraviolet radiation of the sun, and unlike wood pilings, they do not contain potentially-toxic chemical preservatives.
#5 Composite Sheet Pilings
Similar to vinyl sheet pilings, composite sheet pilings are made from a composite material, such as fiberglass-reinforced polymer, which provides the strength of steel sheet pilings, with reduced weight and better resistance to corrosion and weather damage. They are also more cost effective than steel, with lower shipping costs, and they do not contain any toxic chemicals. Composite sheet pilings are similar to vinyl and steel pilings, with large vertical sections formed with ridges or channels. They are driven into the ground in a similar fashion and can be used with or without vertical pilings, and they require very little maintenance once installed.
#6 Composite Pilings
Made from a composite, such as fiberglass-reinforced polymer, composite pilings are used in place of treated wood pilings or timbers, which have a tenancy to decay after several years. Composite pilings are much lighter than wood pilings, and they are not susceptible to water damage, fungal decay, insect infestation or other problems frequently associated with wood pilings. They are cost-effective compared to wood pilings, and have a much longer lifespan. Composite pilings can be used alone or in conjunction with steel, vinyl, composite or aluminum sheeting systems.
#7 Aluminum Sheet Pilings
Another alternative to steel sheet pilings are aluminum sheet pilings, which are similar in strength, but weigh less than a third of similar steel products. They are not as susceptible to corrosion or electrochemical reactions as steel, and they are easier to transport, maneuver and install at the job site. They are available in standard vertical interlocking sheets, and are driven into the ground like other sheet pilings. They will last longer than steel, with a comparable cost over the lifetime of the product.
Other Parts and Accessories
The pilings and sheeting form the main structure of the bulkhead, but here are many other parts that are critical. In the soil behind the bulkhead, poles called deadmen are driven or buried, then connected to the bulkhead with tie rods or wire to support the weight of the wall. The top of the bulkhead can be capped to increase its rigidity and add a finished look, and wales can be added for protection.
By choosing the materials for your bulkhead carefully, you can reduce your maintenance costs, extend the lifetime of the bulkhead and avoid costly replacements in the future.