Block Wall Alert—TILT!

Tilted retaining wall

When purchasing a home, especially a resale home, be sure to walk around the outside of the entire property or you might be surprised at what you find after your purchase. The phrase, “buyer beware,” still applies when it comes to purchasing real estate.

This situation occurs more often than you would think when it comes to older or historic properties dating back 40 years or more when building codes and construction industry standards were less stringent than today.

Exterior photo of wall & vegetation

We were asked to visit a property in scenic Palm Springs, California, to observe a failing retaining wall at the rear of the property. It’s a beautiful modern home set into a hillside with a sparkling pool, views of the desert and city lights; a place that anyone who enjoys the desert would love to call home.

This exterior retaining wall, however, was covered with vegetation and was not observed by the new owner (nor disclosed by the prior owner) or revealed by a professional property inspection at the time of purchase. The wall was supporting the backyard and pool area, but was not designed or constructed properly, and it had been tilting for years.

Tilted & damaged retaining wall

Here’s a tip: many times homes are purchased for cash and there is no property inspection required because there is no mortgage. Don’t skip this step in order to save a few hundred dollars on a reputable home inspector; you risk spending more to fix unseen damage or problems. In situations involving the purchase of hillside homes in Southern California, many times it also is a best practice to retain the services of a consulting engineer to inspect hillsides, block walls and foundations before purchase. Professional structural engineers will likely observe problems that home inspectors, who are typically not engineers, might not observe, note or require a repair in a standard inspection report.

The Post-Purchase Inspection

After observing the distressed wall, we knew the first step would be a full geotechnical investigation which consisted of the following services:

• Excavate two test pits to maximum depth of about four feet to expose the existing wall foundation.
• Excavate two borings to 25 feet (one day of field work) and obtain undisturbed soil samples. Perform geologic observations, describe and log the soil samples.
• Perform laboratory testing on the recovered samples, consisting of strength, moisture/density, compressibility, and chemical content.
• Prepare soils report with underpinning stabilization recommendations.

Here’s another tip: the Palm Springs area periodically experiences earthquakes.

Desert soil is sandy and can be unstable—especially in hillside areas. The combination of these factors along with older construction techniques and materials can be problematic over decades of time. What might have worked for a home’s original builder and owner decades ago can and likely will deteriorate over time.

The Solution

Rebuilding the retaining wall

We also were retained to prepare the repair structural plans and details in accordance with the geotechnical report recommendations. We performed multiple geotechnical and structural observations during removal of the old wall and constructing the new wall.

Extensive work needed to be done to ensure that the new wall would be constructed properly. The problem is now solved for the new homeowners who will enjoy decades of worry-free swim parties in their Palm Springs hillside home in one of the state’s most admired, premiere resort communities.