The Problems with Plate Anchors for Structural Foundation Repairs
When a foundation wall is damaged by settling or by lateral pressure from swollen soil it places the entire foundation at risk. Whether the foundation wall is poured concrete that has cracked and begun to rotate inward or concrete block or other masonry that is bowed or bulging in the center, a damaged wall left unrepaired can disintegrate and collapse. This leaves an entire section of the house unsupported and causes systemic damage throughout the structure.
There are a number of different ways to repair a damaged foundation wall but they all ultimately do one thing – stabilize the wall completely to prevent any further movement. Whether it’s an older method like bracing with a steel I‑beam or a more modern approach like using low-profile channel steel or carbon fiber, the goal is to counteract the outside pressure on the wall before the damage gets any worse. One method, however, has more than a few faults and homeowners should think twice if it is recommended to them as a permanent solution.
What’s Wrong with Plate Anchors?
The plate anchor is an older method of stabilizing a damaged foundation wall. Multiple excavations are made a distance from the damaged wall and a steel plate is inserted in each hole. A corresponding hole is drilled through the foundation wall at each spot and a threaded rod is inserted and manipulated through the soil until it reaches the hole. The rod is attached to the steel plate and the hole is backfilled, then a corresponding steel plate is attached to the rod on the inside and nuts are tightened until tension is created. This is intended to stabilize the wall by preventing further inward movement. The system requires periodic tightening by the homeowner for the foreseeable future.
In theory, this should work; in practice, the approach has some problems.
Disturbed Soil – In order to remain in place and create the proper tension, the buried plate must be in undisturbed soil. If the plate is placed incorrectly it will move, tension on the threaded rod will be lost and the wall will no longer be stabilized. In a modern residential neighborhood, it is difficult to find truly undisturbed soil – the typical residential area has been built with multiple foundation excavations and extensive grading across multiple home sites. Fill soil has often been trucked in to building sites and tree stumps have been removed, making it less likely that soil has been undisturbed.
Maintenance Required – Even if the soil conditions are absolutely perfect, there will still be some movement and loosening of the plate anchor system. This means that the homeowner must maintain the system by periodically tightening the fittings on the inside; failure to do so means that wall movement will resume. This maintenance can be difficult for smaller or older homeowners and any plans to finish the basement space must include access points for each of the multiple plate anchors.
No Immediate Result – Because of the issues with soil and the required maintenance, it can take much adjustment and tightening of a plate anchor system before the wall is completely stabilized. This can force the homeowner to delay plans to sell or remodel the house.
Repairs are Obvious – Even a successful plate anchor job leaves behind much more than a telltale sign – large steel plates bolted to basement walls. This can be at best a red flag and at worst a deal-breaker for a potential buyer.
There are several better ways to stabilize a foundation wall and a homeowner with foundation damage should be careful to choose a foundation repair contractor that can recommend the right choice. At U.S. Waterproofing, our foundation repair experts frequently recommend carbon fiber or channel steel repairs to stabilize foundation walls and they do so based on years of experience and many, many satisfied homeowners. Why not ask us for a free consultation on your foundation problem?