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My Store: San Marcos
Marine Timbers and Treated Lumber

Marine Timbers

Choose the Best Marine Timber for Your Seawall

Pressure treated lumber has been synonymous with marine use for many years. The cost of marine-grade timbers compared to other types of materials can prove to be more economical, with a properly engineered seawall or retaining wall lasting up to 25 years when adequately maintained. Marine timbers can also give your waterfront a more natural look. Marine timbers and posts are constructed from the heartwood of Southern Pine material, and then pressure treated to the rigid specifications necessary to qualify them for use in varying marine applications. In order to keep marine timbers as fresh as possible for our customers, McCoy’s offers marine-grade treated lumber through Special Order.

Advantages of Pressure Treated Wood in Marine Applications

Pressure treated pine is popular for marine applications because timber pilings are strong and sturdy while still being flexible enough to resist wind and wave thrust, minimizing erosion and increasing flood protection. A renewable resource, marine timbers are less expensive to purchase and install than concrete or vinyl sheet piling, and repairs can be made quickly and efficiently. Treated wood will not rust, corrode or crumble over time like concrete. Wood is also more accepting and secure for fastening devices like screws, lag bolts, ring-shank spikes or nails.

Pressure Treatment Levels and Requirements

Pressure treated pine is ideal for both fresh and salt water applications (with salt water applications following more stringent guidelines when it comes to the level of treatment). Choosing the right type of chemical treatment level depends on the specific use for the product. McCoy’s suppliers use a CCA treatment which is both dependable and approved by the American Wood Protection Association when used in a marine environment as recommended.


Treatment LevelFreshwater (MCA or CA)Saltwater (CCA)
.06Above Ground Contact (decking joists and deck boards)Above Ground Contact (decking joists and deck boards)
.15Splash (Ground Contact) 
.23Full Immersion 
.60 Saltwater Splash
2.5 Full Saltwater Immersion

Components of a Marine Timber Seawall

McCoy’s Building Supply carries a variety of wales, caps and tie-rods to complete your seawall project. Please contact a McCoy’s store that offers marine products to speak with someone about creating a Special Order for your project that will include all the components you’ll need.


Wales minimize the movement in your seawall panel by dispersing pressure along the wall and transferring it to the anchors through the rods. Wales can be made out of treated lumber, steel, concrete, aluminum and composite tubes. 


Caps are aesthetically appealing and help give your seawall structural rigidity. They can be made of concrete, treated wood and composite or treated decking.  


Tie-rods come in a variety of materials including stainless steel and galvanized steel and are often the first component of a sea wall to fail because of exposure to corrosive salt water. McCoy’s currently offers hot dipped galvanized (HDG) steel tie-rods at most locations carrying marine products. The galvanizing compound coats the steel tie-rod with a layer of zinc to give it a longer life.  

Typical Marine Applications

Pressure treated pine has long been the preferred material used in the following marine applications.

• Bulkheads/seawall• Coastal boardwalks
• Fishing piers• Marina boat slips
• Boat docks• Sand dune crossovers
• Boathouses• Elevated beach houses
• Elevated beach access walkways• Beach retaining wall
• Lakefront retaining wall• Erosion control structures


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