Which Is Best: Helical Wall Anchors or Plate Wall Anchors?

Components

• Helical anchors, also referred to as screw anchors or helical tiebacks, consist of an interior wall plate and a helical anchor. Plate anchors consist of a plate, an anchor and a rod that are tied together when installed. Both systems are designed to exert outward pressure on a bowed or cracked foundation wall to force it into a straighter position.

Installation

• A helical anchor is screwed into the soil through a hole that is predrilled through the base of the foundation or retaining wall. The anchor is secured against the wall using a wall plate on the interior side of the wall. When installing a plate anchor, a plate is bolted to your basement wall using a rod that is held in place with a bolt. Then a hole is drilled through the wall and a trench is dug into the soil outside. The rod goes through the wall into the trench where it is fastened to another plate placed into the ground up to 10 feet from the wall and the trench is filled in with soil again.

Function

• Both types of anchors serve the same function; to repair or stabilize a bowed or cracked foundation or retaining wall. With a plate anchor, the plate in the ground is stabilized by the soil beneath and on top of it. The bolt on an above-ground plate can be tightened periodically to put more pressure against the wall and force the wall into a straighter position. A helical anchor is supported by the soil it is driven into, stabilizing both the soil and the wall. The force exerted on the wall plate forces cracks to close and limits further bowing.

Advantages

• The type of anchor that is best for your foundation or retaining wall depends largely on the soil and how much disturbance to the exterior of your home you can handle. Helical anchors provide permanent stability with minimal excavation because the anchor is driven into the ground via a hydraulic torque motor. A plate anchor requires that a trench be dug, making the disturbance greater. Plate wall anchors are the most inexpensive option, though they require regular tightening of the plate screw to ensure that enough pressure is given to the wall to keep it straight. Helical wall anchors don’t usually require this maintenance. In loose soils, helical anchors can provide more stabilization than a plate anchor because they can be drilled through the loose soil and into the deeper, more stable soil beneath.