Corrosion appears to have caused the collapse of a facade on Grace Street earlier this month, according to an engineer who reviewed the aftermath.

The exterior facade, which collapsed on March 7, runs above the storefronts that house Taco Baby, Kat 5 Kava and Rumcow. While the collapse forced initial closures, some of the businesses have since reopened.

Within days of the collapse, E.B. Pannkuk, president of local firm Stature Engineering, reviewed the building with building owner Bruce Umstetter. Umstetter has owned the building since 1984, according to property records. The building near the corner of Grace and S. Second Streets was built in 1940. 

Although Pannkuk’s firm didn’t perform a formal failure evaluation, a review found that a “steel window lintel weakened by corrosion” appears to have contributed to the collapse.

“We did observe one area of the lintel that was displaced,” Pannkuk wrote in an email to the Business Journal. “Eye witness accounts appear to support our assumption.”

Following the collapse, Project Grace contractor Monteith Construction received questions about whether the site’s ongoing work could have affected the nearby facade, Monteith President Bryan Thomas told the Business Journal last week. 

“We don’t think there's any tie to it,” Thomas said, adding that the site has several measures in place to limit vibrations.

Monteith has worked on renovations of about 20 downtown buildings over the years, Thomas said, and it’s not uncommon for aging facades to have problems.

“What we've seen on old buildings is just years of water intrusions, and ultimately, that just starts to break down the brick and the ties that hold the brick to the facades,” he said last week.

It’s “doubtful” construction in the area contributed to the collapse, according to Pannkuk.

“A vibration with the strength to damage adjacent buildings would have to be incredibly strong,” Pannkuk wrote. “We do recommend that buildings have a third-party testing company document the existing condition of adjacent buildings. This documentation goes a long way toward settling debates over construction damage.”

He added that periodic building evaluations by an engineer with experience in historic construction could have made the facade collapse less likely.

“This could be an issue in other buildings in downtown Wilmington,” Pannkuk wrote. “Building owners should have their building reviewed to improve general building maintenance.”