A helical tieback is a system that includes a metal shaft, called an extension rod, with metal plates on one end, known as helical plates, that are screwed into the soil. The other end of the extension rod is threaded, so you can screw the entire assembly into the earth with a high torque drill. The use of helical tiebacks to stabilize existing retaining walls is an economical way to treat the problem of a shifting or bowed wall. Often, a retaining wall moves because of the structure of the subsoil. If the subsoil is not stable, it can shift, creating pressure on the wall. This pressure will eventually cause the wall to bow, shift or crumble. Installing a series of helical tiebacks allows you to use the soil as a brace, to stabilize the wall.
Things You'll Need
- Helical tiebacks
- Masonry bit
- Drill with high-torque motor
Drill a small hole through the retaining wall with a masonry bit. You want to install the helical tiebacks about halfway up the wall.
Excavate the soil outside the hole, so you can place the bearing plate against the hole.
Place the screw anchor in the opening you drilled in the wall. Use a drill with a high-torque motor to drive the screw anchor system into the soil. Follow the manufacturer's recommendations for depth and torque.
Remove the anchor end of the screw, which is on the face of the wall, and replace it with a smooth metal plate that comes with the helical tieback system.
Repeat the process down the length of the wall. Grip-Tite, which manufactures earth-anchoring products, recommends placing helical tiebacks every 5 feet.
Tips & Warnings
- Always wear safety goggles and a dust mask when drilling through masonry.
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