Wood Retaining Walls
Wood retaining walls can be substituted for retaining wall blocks construction more cost effectively if the wall is relatively small (no more than 2-3’). Pressure treated lumber of several dimensions can be used to create a wall, planter box or garden border. Steps can be integrated into wood walls quickly. Concrete or brick pavers can be used as step treads. Pressure treated timbers create a more rustic landscape design and are often used on a project where the wall is not seen regularly.
Taller 3”+ timber retaining walls should follow engineering guide lines. Dead men or purling must be used on the soil side to hold taller wood retaining walls in place. Buttressed walls can be used when there is no room on the soil side for dead men. Buttresses are supporting beams or boxes on the open air side of the wall that add strength. They are often disguised as planter boxes and integrated into the design. Without these features, wood walls will lean, bulge and eventually fail.
Wood walls need to be designed and built to the correct engineering standards to ensure the walls will not fail prematurely. A large part of the correct standards is building in the anchoring structure known as “dead men” or perling. This picture illustrates how a wall should be built.
Treated timber walls should have dead men anchored as deep into the soil behind the wall as the wall is tall i.e. A 4’ tall wall should have a 4’ dead man false wall anchored behind it. The forces pushing on the wall then have to pull the false wall through the backfill soil before the wall can fail and blow out. This wall was added to a 5yr old existing wall. We had to remove several extra timbers to find solid wood to anchor to so our dead man structure was even more important.
Timber retaining wall construction projects is something do-it-yourselfers can tackle if they have the right tools and time. See our how to build retaining walls page for tips and suggestions.
A correctly engineered and installed treated timber wall will last 10-15 yrs. This picture shows that even a well built wall will begin to fail and pull away from its anchors as the wood ages and becomes softer. These walls are less flexible from a design stand point and do not weather as well or last as long as other choices. Due to engineering requirements for taller walls and the associated material costs, taller timber walls quickly become as costly as segmental retaining walls and still won’t last a life time. Most customers choose block retaining wall systems once the advantages are brought to their attention.
Sea walls or waterway walls can be a great way to control erosion and stabilize the soil in the waterline. Treated lumber is an excellent choice for this application. Verticle pilings can be driven into the bank or concreted. The timbers or even treated boards can be placed between the pilings and soil and backfilled with rock or soil. Cap the wall with a board wide enough to stand or sit on for a finished look. In this application, we even ran out door lighting along the top of the wall. Let us create a plan to beautify and stabilize the bank of your waterway project. Contact us here to get your free estimate.