A popular Wal-Mart store in Corona, CA, was originally surrounded by a large, stacked block wall 1,400 linear feet in length and more than 20 feet high. Unfortunately, movement was discovered in the wall, creating a dangerous scenario that threatened several homes above and behind it as well as initiating other safety concerns for the entire area.
Baldwin Construction, a drilling contracting company from Carlsbad, CA, was hired to anchor and stabilize the wall. A tieback system was used in which a multitude of deep holes, eight inches in diameter, were bored into the soil behind the wall. Next, 80- to 100-foot-long cables were lowered into the holes and grouted. Large, flat metal rings were installed over the holes. A large machine pulled on the plates, which slid the cables, forcing the retaining wall back into its proper place. To permanently hold the wall, large steel nuts were attached over each plate.
Wal-Mart executives were pleased with the first phase of the work, but it looked raw and unfinished. The drilling contractor had no choice but to leave large steel plates that were visible everywhere, sticking out 10 to 12 inches in some places throughout the entire length and height of the 20-foot-high wall.
How could such a significant architectural element surrounding the store be made more aesthetically pleasing? What options were available? An initial thought was to use cast-in-place concrete to create a new face for the wall, but that process is time-intensive and extremely expensive. They needed to find a more affordable, fast, and effective solution.
Boulderscape had been involved since the beginning of the project due to a long-standing relationship with Baldwin Construction. “We’re fortunate to have Boulderscape on our team,” says Paul McKee, Baldwin Construction vice president. “We’ve worked with Boulderscape over a number of years, and we are always extremely happy with the results, and so are our customers.” McKee explains that the team approach with Boulderscape starts at the proposal level of each project. “It truly creates a win-win and allows all of us to be part of the planning process, knowing that when we leave a job site, we’ve covered all the details and the client is left with a beautiful, custom-looking wall.”
Steve Jimenez, vice president with Boulderscape, came to assess the situation months earlier before work ever began on the stabilization of the wall. Because there was no visible geology available nearby to replicate, Jimenez determined that a sandstone finish with some natural-looking cracks could make the wall appear as if it were a recently excavated cut slope. “I believed it was the perfect choice for the size and scope of this project,” he says.
“Our popular sandstone finish is easy on the eyes because the colors are soft and the shallow cracks add even more softness to the look,” he says. “Wal-Mart executives quickly approved the photo simulations we provided with Photoshop because we were able to show what their specific wall would look like with our custom-designed shotcrete finish before the project ever got started.”
Once the initial plan was approved and the stabilization portion of the project was completed, the Boulderscape team moved into high gear. There are three key steps to the process. First, crews began by installing a very thick layer of structural shotcrete, about 8 inches thick, to the wall face, section by section. A second architectural shotcrete layer, 1 to 3 inches thick, was then applied. “While it was still wet, our expert artisans came in and produced the approved finish into the wet concrete, sculpting a fractured sandstone look with free hand,” says Jimenez. “The final step was the application of stain, which brought the colorless surface to life. The entire process took six experienced team members a total of 14 days-half the length of time it typically takes for other types of wall finishes.”
Boulderscape’s solution also saved Wal-Mart money. “Our technique is 30% to 40% less expensive than traditional cast-in-place form or form-liner finishes,” Jimenez continues. “It’s also 40% less than an architectural stone veneer, which is another popular façade these days.”
“It’s natural-looking, cost-effective, easier to expedite, and, ultimately, for the kind of work we do, it’s more of what our clients are looking for,” says McKee. “Boulderscape did a beautiful job with this retaining wall.”
Jimenez reinforces the importance of the team effort. “Because of the collaborative attitude of everyone involved, we were able to turn what might have been a disastrous initial situation into an aesthetically pleasing and highly believable looking retaining wall that is now safer and more secure than ever before.”
