A “slope failure” that last month forced 91 owners to evacuate from their homes in one of Centex’s subdivisions in San Antonio has led that city to take a much closer look at the structural integrity of retaining walls in all of its residential communities, as well as a permitting process that, depending on who you talk to, until recently has been either ambiguous, mostly ignored, or remarkably lax in its enforcement.

After meeting on Wednesday with officials and 50 members of the Greater San Antonio Builders Association, San Antonio’s Department of Planning and Development Services informed builders that, contrary to what many apparently believed, building codes require them to obtain permits for all retaining walls higher than four feet. "There's nothing ambiguous about this code," says Barry Archer, the department's assistant director. But compliance has always been on the "honor system," he explains, given his department's limited staff of inspectors.

However, San Antonio now is taking a harder line with builders, which have until March 31 to apply for permits retroactively on all retaining walls that they’ve built since 2007, and to provide the department with documentation that these walls were designed by structural engineers and have been installed properly.

The Department of Planning and Development Services is also exploring an amendment to the city’s Unified Development Code “to reinforce the procedures for permitting retaining walls during all phases of construction.”

Given that few builders had been applying for retaining wall permits, providing three years’ worth of structural documentation could be difficult, according to builders interviewed by the San Antonio Express. The city also did not specify how it would address deficiencies in retaining walls constructed by builders that no longer operate in San Antonio. "We'll just have to cross that bridge when we come to it," says Archer.

Centex, which is now owned by Pulte, did not pull a permit for the 20-foot high, 1,000-foot long retaining wall that surrounds its Hills of Rivermist subdivision. A structural engineer designed that wall and oversaw its installation, said Pulte spokesperson Valerie Dolenga. But on Jan. 21, the retaining wall holding up this community’s hillside gave way, as the ground around numerous homes opened up, by as deeply as 30 feet in some spots.

In an interview with BUILDER on Thursday, Dolenga confirmed that the city has suspended the certificates of occupancy of 27 of the evacuated homes in this neighborhood. (Three of those homes have foundations that are are now being buttressed by piers beneath them.) Pulte continues to provide housing and per diems for families that have not been allowed to return to their homes, and last weekend discussed longer-term housing options with these families, Dolenga said.

For the 64 families who are back in their homes, Pulte this week began offering free inspections for damage or defects, using a third-party company that was not involved in either the construction or the post-failure evaluation. San Antonio’s District Fire Chief Nim Kidd tells BUILDER that his department is still “monitoring” this subdivision, which the city now considers to be a “construction zone.” His department’s emergency response services has included text-messaging owners to keep them informed of events after the evacuation.

Pulte has also hired Kansas-based Terracon Consultants, a national engineering firm, to assess the stability of the grounds of the subdivision. Dolenga said Terracon has two objectives: to find out what caused the ground to split open and how to fix it; and to figure out why only certain areas of the subdivision were affected by slope failure.

She says Pulte expects the engineers to deliver their preliminary findings by early March. Pulte will provide documentation and test results to the city’s planning department. And over the next 90 days, the builder will be looking at the structural integrity of retaining walls at all 20 of its communities in San Antonio.

John Caulfield is senior editor for BUILDER magazine.

Learn more about markets featured in this article: San Antonio, TX.