Wood Seawalls

Seawalls are constructed from 2” x 8” Rough Cut Wood Boards especially heavy-duty pressure treated (for fresh water use) to a retention of .60. This means a much higher concentration of chemicals are pressured to completely penetrate the complete inside of the rough cut lumber, saturating the whole board rather than just the outer layer. This provides the wood with a much better protection from various fresh water bacteria, thus guaranteeing the wood a much longer life span. The standard treatment for pressure treated or wolmanized lumber is to retention of only .25.

Ground penetration of the boards and required board length is dependent upon the desired elevation of the wall above ground level, minimum ground penetration being 2 feet, minimum board length being 4 feet. Support 6” x 6 pilings are jetted into the lake bed in front of the wall every 8 feet. Pilings must be set 2 foot deeper than the vertical boards. All lumber will be rough cut 2 inches thick 2 layers of 2 x 8 pressure treated pine rough cut boards are framed to the pilings, one layer at the top of the wall, the second layer near the base of the wall where possible according to amount of the wall elevating out of the water.. Each layer will be over lapped for strength. Vertical wall board lengths vary depending on location elements. Boards must always be long enough to prevent future kick out at the base of the wall. The 2 x 8 rough cut boards are jetted into the ground side by side & nailed to the upper 2 x 8 double framing & the second layer of framing near the base.

The back of the wall is then covered with a lifetime warranted filter weave screen Phoenix W-70, 12 feet wide from the top of the wall to an overlap at the bottom. The screen is stapled to the back of the wall & is covered at the top of the wall with a single 2” x 8” rough cut pressure treated pine board. The porous filter weave screen allows water to pass through it but prevents any back fill from filtering through the wall. The framing front & back at the top of the wall is then bolted together with 5/8” hot dipped galvanized machine bolts with 5/8” galvanized washers back & front. These bolts are set every 6th board which is approximately every 4 feet.

The wall is secured by 5 foot 6 inches long, 6”inch base plated screw anchors, set at 8 foot intervals behind each piling. The anchors will be screwed deep below ground level & set in concrete. The anchors are set approximately 8 to 10 feet behind the wall (where possible). The wall is secured by attaching 5/16” stainless steel cable to the anchor arm with nicro sleeves crimped around the cable, then extended to an eye nut secured to the inside of the wall bolt. The wall bolt that goes through the piling, the double framing, the vertical boards, the screen & the back framing boards. The anchoring cable is looped around the eye nut, pulled back really tight to the anchor arm with come along pulleys then crimped with 5/16” inch nicro sleeves with a heavy duty crimping tool to secure the wall permanently in place.

When the wall is complete the anchors and securing cables are below ground level at the back of the wall and will be covered completely with fill dirt. The seawall will have a wooden cap constructed of 2” x 8” rough cut pressure treated pine. The cap will be nailed onto the seawall framing with 20 penny hot dipped galvanized nails.