Retaining Wall Construction Building A Timber Retaining Wall Developed by: Dr. Teri Hamlin Georgia Department of Education

Timber Retaining Wall To level a steep slope Enclose an area for a decorative garden Elevate Beds

Which wood? Treated pine and hardwoods are good choices for a timber retaining wall. Avoid old railway timbers as these are treated with creosote, which harms some plants and heavy to work with. Also need reinforcing rods secure the structure.

Steps: Cut a beveled trench into the slope, wet the trench and tamp it well.

Steps Set the first timber in place and level it. This course will be completely buried in the ground.

Steps The timbers are installed in a pattern similar to a brick wall with the butt ends of timbers in one course offset from those in the courses above and below.

Steps Set a second timber on top of the first and bore a hole through the two timbers. Use a heavy-duty drill with an extension bit. – A small bit burns out on long holes such as these. Drive a reinforcing rod through the holes into the ground to hold the timbers firmly together.

Steps In addition to the 15 degrees inward slope of the wall, vertical stability is achieved by installing tiebacks. These are single timbers inserted perpendicularly from the face of the wall into the soil backfill to a distance equal to their height above the base of the wall.

Steps Continue to lay the timbers – staggering the joints from one course to the next Drill holes and use a reinforcing rod to pin each timber to the one below on each side of every joint. Cut timbers with a sharp chain saw, and wear goggles to protect your eyes from flying chips.

Steps Backfill where necessary. For drainage, – Drill weep holes along the wall's length – Drill a row of holes above the ground

Steps Fill the cavity. You can top off the terraces with plantings or mulch.

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