In a previous post, I discussed the different types of cracks you may commonly see throughout your home and in foundation walls. In this post, we’ll go over some of the most common options for repairing displaced foundation walls and some of the pros and cons of each option.
It is common for foundation walls to move inward over time as a house settles and experiences pressure. This pressure comes from the freeze/thaw cycle, hydrostatic (water) pressure, expansive clay soils, large tree roots, and other factors. Foundation walls are designed to support load from above, not from the side, and if the pressure from soil is too great for too long, the wall will begin to move inward because it can’t resist the force. As this happens, evidence (such as cracking) will indicate that the wall has moved and may need dealt with to avoid a structural failure. If you notice displacement (bowing, buckling, etc.) of your foundation walls, be sure to deal with it immediately.
At times, a foundation wall is so bad that the only viable solution is to dig around the exterior and replace the wall. Fortunately, though, in many cases the wall can be dealt with from the interior, which saves a lot of work and expense. Some of the most common interior repair options are steel I-beams, helical wall anchors, and carbon fiber strips. Knowing which option to go with requires some basic knowledge of how each option works.
A common steel I-beam option requires that the contractor digs into the concrete floor at the base of the wall, installs I-beams vertically against the wall, and secures them to the floor joist system above. I-beams are in the shape of an “I” – hence their name. Once installed, the dug portions of the floor are refilled with concrete so that the beams become a permanent part of the structure at the foundation and prevent any further inward movement of the wall. A downside to common I-beams is that they are not very visually appealing and take up some space along the wall. If the basement is not finished and the beams are exposed, this isn’t an attractive option to some homeowners. Fortunately, there is an option called “channel steel,” which has a lower profile but still possesses the strength of larger I-beams, and many contractors now use channel steel to ensure a good repair with more visual appeal.
One I-beam system, called the “PowerBrace” system, utilizes large screws at the top of the beams that can be turned periodically over time to exert pressure and eventually force the wall back into proper alignment. The I-beams for this system are installed with an anchor at the base, eliminating the need for digging out portions of the concrete floor.
Helical wall anchors are installed by helicals (large screws) being driven into soil at a depth that is not affected by freezing, temperature changes, moisture, etc. A metal plate and anchor are installed on the interior side of the wall, as well as an earth anchor in the ground. The opposing sides from the soil and wall are connected by a rod and exert pressure in opposing directions. This counteracts hydrostatic pressure and pulls the wall back into alignment and prevents further inward movement; and this system does not take up the space that I-beams do. The installation of helical wall anchors requires some precision planning and load testing. Some exterior excavation may also be required, depending on the method used. In short, it can be a bit complicated, so some contractors do not have the capability of installing them properly.
In more recent years, carbon fiber strips have become very popular as an easier, less obtrusive, and often more cost-effective method for foundation repair. Carbon fiber is one of the strongest materials available (about ten times stronger than steel), and it is extremely good at resisting force. Carbon fiber strips are installed by sanding down the vertical areas where they will be placed, applying a two-part epoxy, and adhering the strips to the wall. If properly installed, they tend to do a good job of preventing the wall from moving any farther inward because as the wall attempts to move inward the carbon fiber resists the pressure and does not stretch. Imagine a rubber band attached flat against your finger versus a piece of metal. As you bend your finger, the rubber band will easily bend with it, but if you attempted to bend your finger with the metal on it, your finger would not move at all. Carbon fiber strips lie flat against the wall and can be painted over after installation, allowing for a non-obtrusive and more visually appealing option. Unfortunately, carbon fiber strips can only be used on walls that have moved inward less than 2 inches and that are generally consistent. Therefore, they are not an option for severely bowed walls or walls with significant and varied cracking. They are also most effective with walls that have moved inward toward the center and are not as effective with walls that have moved inward at the bottom or top. And unlike some of the other options listed here, current carbon fiber options are not capable of forcing a wall back into alignment.
If you have a foundation wall in need of repair, the best option depends on several factors. Is the wall displaced more than 2 inches? Are you concerned with bringing the wall back into alignment, or merely preventing the wall from moving inward any farther? Are you intending to finish over the wall or leave the area exposed and visible? Does the wall’s appearance matter to you if it will remain visible? Is it the top, middle or bottom area of the wall that has moved inward? These questions, and others, will all have an impact on determining the best option for your particular needs, and the qualified contractor you hire to perform the job should be capable of guiding you in your decision.
Fortunately, the options mentioned are less costly than you might assume. They also don’t typically take much time. In addition, most foundation repair contractors and companies guarantee their work for at least ten years, if not for the entire life of the home. Do your homework to determine the best contractor to hire based on their experience, the method they plan to use, cost and warranty. Armed with the knowledge of this article and a reliable, trustworthy contractor, your foundation repair will likely be less troublesome and costly than you might have assumed.
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