5 Factors to Consider When Choosing Bulkhead Material

Posted on August 20th, 2015 by Aaron Presley

Erosion, toxins, longevity, wood-boring insects, aesthetics… there are many factors to keep in mind when choosing bulkhead materials, but the selection process is far more exciting than it was two decades ago. Today’s fabricators have made great strides towards achieving the lifelike look and texture of natural materials using vinyl. Even so, the rustic look and weight of wood is irreplaceable, and you no longer need to concern yourself with much erosion and buckling. Today’s timbers are treated to add strength and even to mimic more expensive alien wood species.

-1) Vinyl

Think of bulkhead materials as an investment. While vinyl’s upfront costs may seem tough to stomach next to cheaper materials, its lifetime is significantly longer. Vinyl is usually expensive, but it lasts over 50 years, which means its annual costs are lower than those of timber and steel.

• It’s lightweight and doesn’t absorb moisture, which makes it a dream in marine applications and seawalls.
• It doesn’t corrode.
• It resists buckling.
• Because vinyl is so light, it needs lighter tools during construction, which saves you time and money.
• Wood-boring insects are, of course, not a problem you’ll have to face with this material.
• When the wood surrounding your bulkhead needs replacement, you needn’t invest in more vinyl.

-2) Timber

The natural look of wood gives you a retro, organic aesthetic at a low upfront price. Its longevity is half that of vinyl, but treatments can extend its lifespan significantly. Your wood will last you about 25 years, but it’s prone to buckling and cracking. If your location and weather exposure aren’t challenging, your wooden bulkhead will last longer.

• If you’re buying wood for marine applications, your moisture content will need to be between 19 and 21%.
• High-quality heavy timbers tend to be dried and preserved more efficiently than inferior woods.
• Excellent workmanship and design will influence lifespan because wave forces and storm surges deteriorate your bulkhead far more slowly when its engineering is approached intelligently.
• In brackish and salt water, there’s a high number of wood-boring insects, so in this instance, six times more chemicals need to be used than is standard.
• In fresh water, you can get away with a greater variety of treatments and lighter impregnation.

-3) Pressure Treated Wood

Pressure-treatments force preservatives deep into the wood, which adapts it for marine environments. The American Wood Protection Association’s standards for preservatives and chemical retention levels ensure that your wood receives the most durable treatments possible. BMP certified treatments leech fewer toxins into water. If you use quality chemicals and long lasting impregnation techniques, you can use timber in challenging fresh water conditions.

-2) Creosote Preservatives

The ocean is a bulkhead’s harshest enemy, and creosote preservatives have been in use for more than 100 years to overcome the corrosive elements of salt water. They prepare your wooden bulkheads for aquatic environments and are the most cost-effective preservatives for most circumstances. There’s a reason this treatment has been a favorite of the U.S Navy for as long as it has. It gives your wood what it needs to resist rotting in difficult environments.

• It’s perfectly adaptable for under and over water conditions.
• It resists climate-abuse.
• It’s not prone to decay.
• It’s secure against the increased borer activity of seawater ecosystems.

If you have an experienced composite engineer and a supplier who can provide unusually shaped beams and profiles, you’ll extend your return on investment by adding a number of years to your bulkhead’s lifespan.

-3) Wood Pilings

If your bank account is not as full as you’d like it to be, wood pilings are a cost effective option. They’re half as cheap as vinyl, and if installed properly, they’re a true boon when it comes to maintenance. They need very little attention, particularly if they’re treated to keep your bulkhead safe from wood-boring insects. Seawall construction needs customizable materials, something that wood pilings offer in spades. Their aesthetic doesn’t tend to suffer from exposure to sea and sun, so they’re a favorite among homeowners and marine engineers alike.

• They warp less drastically than square timber.
• If they’re polymer coated, their longevity improves.
• There are few industries that the ‘you get what you pay for’ rule applies to more than the marine sector, and while wood pilings are inexpensive upfront, they don’t last as long as composite pilings.
• They leech toxic chemicals into the sea. Even so, there are very few bulkhead materials in today’s world that don’t, so trying to be eco-friendly is a losing battle in this instance.

Round or square options are used, and they’re jetted into the soil using a pump. Alignment is critical, and if your pilings are placed deeply enough, the structure will withstand currents efficiently without the need for cantilevered walls.

-4) Wale and Sheet System

Sheathing boards and whalers guide water gently over the back of the bulkhead so that the entire structure is exposed to less pressure. This system has probably been in use longer than any other, but its light weight can’t tolerate high soil elevations. Its service life is around 20 years, and it can be pressure impregnated to resist marine borers.

• Even treated wood will ultimately rot from constant water exposure, so preservatives need to be impregnated well enough to stay where they’re supposed to instead of being washed away with the current.
• The quality of the chemicals used in your wood will determine the number of years you get out of this system.

-5) Steel and Aluminum Sheet Piling

Steel armor is extraordinarily strong, and its life span is as long as that of timber. An interlocking seal installation is quick and easy to achieve, which reduces your initial investment significantly.

• It can cope with choppy water in marine, and even river, bulkheads.
• It needs to be well coated.
• Its highest service life will only be achieved with painstaking maintenance.
• Steel is far better at holding off corrosion than aluminum is.
•  Both metals have the surface strength to deal with sand and clay onslaughts from the seabed.
• Metal is heavy, which makes it as useful for areas with high soil elevations as timber is.
• Marine borers are not attracted to metal, which makes it a good option if your location has dense insect populations.
• Marine alloys will suit you well when you need extra rust resistance.
• Clay soil causes corrosion that even high-grade steel can’t withstand for long.

List of Sources:

 http://www.creosotecouncil.org/pdf/CCIII_Cost-BenefitAnalysis.pdf

https://www.aimu.org/aimupapers/Docks_Bulkheads_and_Wharfs_2013.pdf

http://www.houstoninspections.com/bulkheadinspections.html

http://nsgl.gso.uri.edu/ncu/ncuh81003.pdf