When there are cracks in a home’s foundation walls, something is wrong.
Not every foundation wall crack is structural; most narrow cracks won’t affect the integrity of the foundation but they can allow seepage. These cracks can be repaired permanently by having a basement waterproofing company inject them with expanding polyurethane.
However, if the cracks are wide (more than 1/8”) they may be allowing the foundation wall to move inward – poured concrete walls rotate in from the top; concrete block or other masonry walls bow or bulge in the center. This is a much more serious problem but it can be repaired.
Two Repair Methods for Structural Foundation Damage: Carbon Fiber vs. Wall Anchors
Carbon Fiber – Carbon fiber repair is the state-of-the-art method for fixing structural foundation damage. Woven carbon fiber strips are applied vertically to the damaged wall, with placement determined by the pattern and direction of the cracks. The spot for each strip is ground smooth to ensure adhesion, a super-strong epoxy is applied and the strip is set into the epoxy under pressure. A steel angle is affixed to the top of the foundation wall to prevent further inward movement and the wall is permanently stabilized.
Wall Anchors – Wall anchors are a more traditional method of foundation wall repair. A hole several feet deep is dug in stable soil approximately 10’ from the foundation. A threaded rod is then driven through the foundation wall from inside so it emerges in the hole in the ground. A heavy-duty steel plate is set in the hole and the end of the rod is affixed to it; a similar, lighter plate is placed on the inside. The rod is then tightened, which pulls the wall back into plumb and closes the cracks. The outside hole is filled and compacted. The number of anchors required is determined by the size and condition of the wall and other factors.
Which Structural Foundation Repair Method is Better, Carbon Fiber or Wall Anchors?
Carbon Fiber – Carbon fiber repair is incredibly strong, requires no excavation and causes very little disruption of the basement. When installed with a steel angle at the top of the wall, it completely stabilizes the foundation. Also, the completed repair creates only small bump on the wall and can be painted or finished over with a normal stud wall. Carbon fiber repair requires no maintenance; its only limitation is that it can be used only when a wall has moved inward two inches or less.
Wall Anchors – Wall anchors can be used no matter how much a wall has moved inward and they do actually straighten the wall when stabilizing it. However, that stability relies heavily on the condition of the soil where the anchor plate has been set. If there is further movement, swelling or desiccation in that area, the wall can de-stabilize. Also, it is much harder to achieve proper yard drainage, as moving water from downspouts and sump pump discharges the normal ten feet away from the foundation will over-saturate the soil where the anchor is buried. Finally, wall anchors require periodic tightening by the homeowner to maintain stability so a finished wall cannot be erected over them.
So, which one is the best? Carbon fiber has the edge most of the time because of its ease of installation, permanence, unobtrusive appearance and freedom from maintenance. When a wall is badly damaged, resulting in inward movement of several inches, the two processes may be combined, with several wall anchors pulling the wall back into position and a number of carbon fiber strips providing permanent stability. The key is employing the expertise to recommend the best, most cost-effective permanent repair that ensures the safety of your home and the use of your basement.
At U.S. Waterproofing, we are experts at installing carbon fiber structural foundation repairs but we also know and recommend more traditional approaches when required. We have prided ourselves on being a full-service resource to our customers since our founding in 1957, so ask us for a free consultation if you’re worried about your foundation.