Layers of wooden boards from a collapsed rowhouse were spread and blocking a small Center City street Friday afternoon, nearly 48 hours after the three-story structure came tumbling down.

The collapse at 320 Butler Ave., around 9 p.m. Wednesday, didn't hurt anyone but it left neighbors in shock and upset that the situation wasn't addressed sooner.

"I'm furious that I was forced to rely on Providence rather than the city of Philadelphia who should have averted what was an obvious disaster in the making to anyone who saw it," Annette Earling, who lives on the same tiny street off Juniper Street, said in an email.

The cause of the collapse had not been determined, Beth Grossman, spokeswoman for the Department of Licenses & Inspections, said Friday. The property had been undergoing a partial demolition, and it was not known whether that contributed to the collapse. The most recent permit, issued June 30, called for the removal of a side wall.

But an inspection of the property indicated that the work done on site, including demolition, went beyond what L&I had approved, Grossman said.

The owners of the property, William and David Cline of Mount Laurel, could not be reached for comment Friday.

The property had been a sore point with neighbors - and the city - for years. It has been slapped with dozens of violations since the Clines bought it in 2013 and started working on it.

In January, the city took the Clines to court in an attempt to get them to comply with demolition permits and a required engineer's report.

"To date, defendants have failed and/or refused to correct the violations by correcting the condition of the party wall and safeguarding the adjoining property," Ed Jefferson, senior attorney in the city's Law Department, wrote in the civil complaint. "The conditions cited as violations present serious and immediate hazard to the safety, health, and welfare of the community in the vicinity of the subject premises as well as the public in general."

Luis Negron, a maintenance man at the University of the Arts dorm building that has windows facing Butler, said the rowhouse has been going through exterior renovations for about two years.

"It was coming along, a nice house," he said.

But about three months ago, Negron said, all the work stopped and the structure was left to the elements.

Grossman, the L&I spokeswoman, said the owners have gone through a number of contractors. One of the Clines' first contractors, in 2013, was Griffin Campbell, the demolition contractor in the deadly collapse of the Salvation Army thrift store at 22d and Market Streets in 2013. Campbell was criminally charged in that event and his trial is scheduled for Sept. 29.

As for the 320 Butler property, a hearing has been set for Tuesday.

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