Case Study - Cracks and Water Intrusion to Basement Walls

Mrs. Stanley* felt like she knew her house well. She had lived in the same one-story home constructed over a walk-out basement for almost 25 years. But like many homeowners, she seldom went into her basement. By the time she reported cracks in the walls to her insurance carrier, the basement was flooding every time it rained.

Mrs. Stanley’s insurance company hired Donan to determine the cause of the basement cracks. Jared Powell, P.E., arrived at the property and took Mrs. Stanley’s firsthand account of her time on the property before beginning his onsite observations. 

The basement’s perimeter wall was constructed of concrete masonry units (CMUs) 5 feet and 8 inches high) and sloped downward from its high point of 68 inches at the west wall. It had cracking throughout, but the most severe horizontal and vertical cracks were on the west wall. Jared also found that the west wall leaned inward as much as 7 degrees.

Paint was inside cracks throughout the leaning wall section, indicating that at some point existing cracks had been painted over. Other cracks were wide and contained no paint, pointing to ongoing cracking. Dark brown stains emanated from various cracks in the wall. Sporadic peeling paint, broken fragments known as spalling, and efflorescence (white salt deposits) were also present.

No paint is inside some of the large cracks, and the concrete is spalled.

The basement walls contained no horizontal or vertical steel reinforcement, no drainage mat or gravel behind the wall, and no underpinning piers or helical anchors at the perimeter footing. Water that collected within the wall had no path to drain, which further stressed the unreinforced walls. Exposed soil between the foundation wall and the perimeter wall was smoothed and damp. Some of the cracks near a basement window had been patched.

On the exterior of the house, Jared noted that the property generally sloped down toward the west elevation, where the cracks were most severe. The gutter downspouts discharged near the corners of the house, and one diverter was partially buried and clogged with debris.

The downspout diverter at the northwest corner is buried and clogged, leading to inadequate drainage.

Based on the basement wall and perimeter wall footing configuration, Jared deduced that the house was originally constructed over a crawlspace that had been converted into a basement prior to Mrs. Stanley’s ownership. However, the CMUs weren’t strong enough to resist the pressure from the external soil, resulting in the wall leaning inward. The lack of drainage provisions behind the wall also resulted in chronic leaking and cracking. The drainage issues were exacerbated by downspouts discharging near the foundation and the property sloping toward the structure.

Professional Engineers adhere to a code of ethics that places the utmost priority on the public’s safety, health, and welfare. To that end, Jared reported to both the homeowner and the insurance carrier his concerns that the improperly constructed basement wall had undermined the perimeter wall footings. He recommended that a qualified professional replace or temporarily shore up the basement wall to prevent further failure and possible injury to the residents.

*Names of all parties outside the Donan organization have been changed.