The foundation is the most critical component of a Houston home. If the foundation is compromised in some way, there could be severe consequences for the entire structure. One of the most serious consequences of foundation damage is wall bowing.
What Causes Walls to Bow?
In most Houston homes, bowing occurs in the ground floor exterior walls. A bowing wall indicates a serious foundation problem that requires immediate attention. That’s because the upper stories and/or the roof of the home are usually resting on the ground floor exterior walls—unless there are additional load-bearing structural components, such as columns, beams, braces, and trusses, which also support the weight of the home. If one or more exterior walls are bowing, they can compromise the stability of the structure above, potentially leading to extensive and costly repairs.
Usually, the outward movement that causes walls to bow is the direct result of two factors: first, most load-bearing walls undergo progressive compressive strength loss over time; second, a series of external forces exert pressure against the foundation, causing it to move upwards—a phenomenon also known as foundation upheaval. When a wall is exposed to these two factors simultaneously, bowing occurs.
The main culprit behind the forces that causes foundation upheaval is hydrostatic pressure. This type of pressure develops when the expansive clay soil underneath your foundation becomes saturated with water. Not only will saturated clay soil expand and push against the foundation; standing water under your home will also push against the foundation and any other elements that restrict its flow. Once all these external pressures exceed the load-bearing capacity of a wall, it will start to bow. Since excess water is the main cause behind wall bowing, this phenomenon is more frequent during the wet season, when water can accumulate under homes due to a lack of proper drainage and grading.
Cold weather is another factor that could contribute to wall bowing. Repeated freeze-thaw cycles can cause clay soil to expand and contract, which might add additional pressure to the ground floor exterior walls.
Because the adverse effects of the expansion-contraction cycles take place gradually over time, bowing walls are commonly seen in older Houston homes. However, inadequate drainage systems, improper backfilling of soil, and poor construction practices could cause walls to bow in newer homes as well.
This problem also tends to occur more often in the homes built on grade-on-slab foundations than in the homes with pier and beam foundations. Additionally, a home built partially below the water table—meaning that its foundation is situated at a lower level relative to the surrounding ground—is more likely to develop bowing walls.
Common Signs of Bowing Walls
An important thing to remember is that walls don’t bow overnight. Bowing is a slow process that might not be immediately apparent. But as bowing worsens over time, you may start to notice some signs, such as:
- Bulging – Bulging along exterior walls is the first sign indicating a bowing wall.
- Wall tilting – A bulging wall may appear that is sliding inwards at the top and/or at the bottom.
- Cracking – Horizontal as well as diagonal and stair-step cracks developing in the affected walls are the most common types of cracks that signal wall bowing.
Here are a few signs indicating that the problem might have been caused by hydrostatic pressure:
- A flood or heavy rain that has recently affected you property;
- Standing water around your home and/or in the crawlspace;
- Excessive evaporation leading to musty odor and mold growth in the crawlspace, under your flooring, and/or on the lower areas of your ground floor walls;
- Negative grading, which directs water runoff towards your home and foundation;
- Efflorescence on the piers under your home or on the crawlspace enclosure;
- Clogged gutters and/or improperly directed downspouts that allow rainwater to saturate the soil around and under your foundation;
- Trees and shrubs planted too close to your home, so their root systems are pressing against your foundation.
When it comes to bowing walls, there are a few remedial measures that can be implemented to address the problem as well as its underlying cause. However, irrespective of the corrective actions recommended, all of them start with a foundation inspection performed by an expert. At Allied Foundation, we provide a free, no-obligation foundation inspection and repair estimate to the homeowners in Houston and neighboring locations. Whether you’ve noticed a few signs of foundation distress, or you just suspect that your home has sustained some form of foundation damage, get in touch with our experts to request a free foundation inspection today!