Lumber Talk

I made a sketchcast about how to build a wood bulkhead and I wrote about how to build a wood retaining wall but I might have assumed too much about how much you know about the bulkhead materials I listed. They are slightly off the beaten path from “regular” building materials you’d find at your local hardware store so here is a breakdown of basic wood bulkhead materials.

Wood Bulkhead Materials List

Building a wood bulkhead is similar to building a privacy fence. You have posts (pilings), rails (wales), and pickets (sheets or sheeting). A bulkhead typically has great horizontal force applied against it, though, so it has more structural requirements than a fence. In order of front to back (water side to ground side) the parts of a wood bulkhead are:

• Pilings (can be round or square)
• Wales
• Center Match (sometimes call “sloppy tongue & groove”)
• Filter Cloth
• Tie Rods
• Deadmen
• Top Cap
• All the required Hardware (nails, screws, spikes, nuts, washers)

Attention: First, the materials required for YOUR wood bulkhead might be different from those I am showing below so please have your bulkhead designed and specified by a professional builder and/or designer. Also, be sure to use the proper materials for the best longevity. Using cheap materials to save money NOW is only wasting money in the long run. Use properly treated wood, galvanized or stainless hardware, and make sure the bulkhead is installed properly.

Treated Pilings

You can use round or square pilings. It is totally up to you. You might want to match your neighbors’ bulkheads or you might be concerned about costs (round pilings cost less). Either way, use properly treated wood – 2.5 pcf in saltwater and a minimum of .60 pcf in freshwater. For brackish (mixed fresh and salt) water, go with 2.5 pcf.

Wales

Wales are the horizontal boards (like the rails on a fence). Most wood bulkheads have two but some will have three or more. Wales are connected to the land-side of the pilings and will have the center match sheets nailed to them. A very common size used for wales is 3×8. You should use the longest lengths possible to minimize joints, which can become weak spots. You should be able to find 3×8-20’s from most marine construction suppliers. Many other sizes are commonly use depending upon the sizes of the bulkhead and the forces applied to it. I have seen wood bulkheads with 8×8 wales.

Center Match

Center match are sometimes called “sloppy tongue & groove” because the joint is a little loose to allow for swelling in the water so the edges will not break with regular expansion and contraction when the boards alternates between wet and dry.

Center match is usually nominal 2×10 with actual dimensions of 1.5″ x 8.9″. That is, because of the groove each board only spans 8.9 inches – very important to factor into your bulkhead materials list. I have heard of numerous people making an extra trip to the dealer (or paying for another delivery) because they were 5 pieces short of center match.

Filter Cloth

Filter cloth is kind of like a very thick felt. The purpose of filter cloth is to stop silt and dirt from seeping through the spaces between the center match while allowing water to drain and relieve hydrostatic pressure from the bulkhead after a rain – it helps maintain a cleaner appearance and keeps soil behind the bulkhead where it should be. While some people use plastic for this purpose, I truly believe a quality geotextile filter cloth is better because it allows the water to drain. Filter cloth is cheap – use it.

Tie Rods

Tie rods support the structure from behind to keep it from falling forward (into the water). Tie rods will be connected to the pilings on one end (via hold drilled from the front to back of each piling) and to deadmen on the other end. They are simply long rods with about 12″ of threads on each end for a nut.

Builders usually use tie rods that are about 3 times as long as the exposed height of the bulkhead being built. For example, a 4′ tall wall will commonly use 12′ long tie rods. The come in diameters including 1/2″, 5/8″, 3/4″, and larger. Some people use cables instead of tie rods but tie rods are stronger and they can easily be tightened if needed.

Deadmen

I have no idea why deadmen are called deadmen but I can make up some good stories about medieval times and using what you have to protect the castle if you want. 🙂

Dead men are treated posts – round or square and often cutoffs – used to “tie back” the bulkhead and support it from behind. Like the rest of the materials, the size of the deadmen used should be based upon the overall height of the wall and the load it bares.

Top Cap

Most top caps are made using a regular S4S 2×12. While they are not required, top caps will provide a little more structural integrity while giving the wall a more finished appearance from above.

Hardware

Use galvanized or stainless steel hardware when building on or near water. Screws are better than nails but more time-consuming. Generally, you will need the following hardware for your bulkhead:

• Tie Rods with 2 nuts and 2 washers for each
• Spikes (60 penny nails) to attach the wales to the pilings
• 16 penny nails (or larger) to attach the center match to the wales and the top cap to the wales
• Staples to attach the filter cloth to the center match

The materials list for a wood bulkhead is pretty simple and short. The bulkhead materials listed above will work for most wood bulkheads or retaining walls built around residential locations. If you need a reliable source for wood bulkhead materials, call the people at Building Products Plus in Houston, TX who let me take the pictures above in their yard. They ship nationwide so you can call them from anywhere.

Here’s a simple sketchcast from WoodScience (became Lumber Talk) on how to build a wood bulkhead.