Foundation Repair: Bowed Concrete Block Walls in a Milwaukee Basement
For many years, concrete block foundations have offered an economical alternative for home builders seeking to reduce the costs (and prices) of new homes. In some parts of the country, including the Milwaukee area and northwest Indiana, block foundations are found in the majority of homes. Properly installed, concrete block foundations can be as strong as poured concrete, particularly when it comes to supporting the above-ground construction.
Where concrete block foundation walls often fail, however, is as the result of movement of over-saturated or shifting soil outside the foundation. These conditions create lateral pressure against the foundation wall that pushes the wall inward, causing cracks in the mortar joints between blocks or, in more severe situations, inward bowing of the wall.
Watching a foundation wall go gradually from flat to bulging can be an unsettling experience for a homeowner, and I’ve had many panicked phone calls from customers who were worried about their house collapsing. In its early stages, wall bowing is easily repairable and should be addressed as soon as it becomes evident because it will only get worse.
What's the Best Foundation Repair Method for a Bowed Concrete Block Wall?
There are many structural foundation repair methods, including inserting steel support rods inside the hollow wall and installing helical wall anchors that essentially pull the wall back against the outside soil. The anchors may work but must protrude into basement space and be regularly adjusted and maintained by the homeowner. Additionally, they are so long that they can cause issues with property lines and, let’s face it; they’re anchored in the same soil that caused the problem to begin with. There are better ways, done from inside the basement with minimal excavation that will maintain the integrity of your foundation.
The traditional interior method of repairing a bowed or bulging foundation was to install steel I-beams upright against the wall. This works to an extent but the rigid I-beam doesn’t conform to the wall so it makes contact at only one point and doesn’t stabilize the wall. The I-beams also ate up a lot of interior space and made it difficult for homeowners to finish their basements.
A newer, more high-tech method of repair is to install carbon fiber-reinforced plastic (CFRP) strips vertically along the wall. Carbon fiber is unbreakable and cannot be stretched so it is an ideal material to prevent further movement of the block wall. The strips are fastened to walls with an equally strong epoxy, conform to the wall and can be easily painted. They are extremely low profile (less than one-eighth inch) and will not interfere with erecting a normal stud wall over them when finishing a basement space.
Steel is still occasionally used on block walls when the mortar has deteriorated to the point where blocks have begun to move independently of one another, creating an uneven surface unsuitable for carbon fiber. Steel is now applied in lower-profile shapes and sizes that are anchored at the top and bottom to provide additional strength. The steel channel makes contact with the wall from floor to ceiling and a jack screw device creates flex in the steel that presses against the bowing wall, preventing any further movement.
Although keeping basements dry has been our business since 1957, U.S. Waterproofing knows that bulging and shifting foundation walls are often the cause or the result of water problems. To provide the best and most complete line of products and services to our customers, we have adopted a carbon fiber foundation repair system and have fully trained and certified our installers in its requirements. additionally, we are fully prepared to make channel steel repairs where needed. If you have questions about what water seepage may be doing to your basement or your foundation, just ask for our free advice. We’ll have an answer for you.
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