Family Court may go down in history as the ultimate stealth building.

Now under construction at 15th and Arch Streets, the scandal-tainted state courthouse was initially outsourced to a private developer and designed in secret. Then City Council quietly rezoned the site to accommodate a bulkier structure than normally allowed. By the time the public learned about the new courthouse, it was virtually a done deal.

On Wednesday, the courthouse almost ducked under the radar again when the Philadelphia Art Commission voted to approve a measure that would add an extra story to the 14-story building. The Art Commission is responsible for approving the design of public buildings.

Minutes later, the commission reversed itself after neighbors pointed out that they had been denied their legal right to comment on the design change.

"This whole project has, from the beginning, been shrouded in secrecy," said Edward S. Panek, who heads the zoning committee of the Logan Square Neighborhood Association. "Let's not leave it there."

The commission ultimately decided to table the issue until its Feb. 1 meeting, but only after a series of procedural missteps.

The request for the design change was made Wednesday by the project's architects, EwingCole. Although the building's foundations are nearly done, the architects decided to increase the height of the courthouse 15 feet, giving Family Court a full floor of office and courtroom space.

Such last-minute requests are rare but not unprecedented. What's odd is that Family Court officials have previously insisted that a 14-story design was the tallest they could build on the site, which is subject to the Parkway's special height limits. Because the ceilings are so high, the courthouse is designed now to top out around 250 feet.

EwingCole told the commissioners that the additional floor was permitted under the existing zoning. But there was no city solicitor present at the meeting to corroborate the claim.

Determining the height and bulk of buildings is normally the province of the Zoning Board of Adjustment, but nothing about the Family Court project has been normal.

In an effort to reduce the cost of building the new courthouse, Chief Justice Ronald D. Castille agreed in 2008 to outsource construction to a private developer.

The deal fell apart after The Inquirer revealed that the court's zoning attorney, Jeffrey B. Rotwitt, had formed a business partnership with the developer and was charging the state exorbitant development fees.

In the wake of the scandal, Rotwitt and the developer were fired, and the state construction agency, the Department of General Services, took over the $200 million project. The agency decided, however, to retain EwingCole's design.

Thanks in part to the real estate slump, construction bids came in lower than expected, around $140 million. Once the savings became clear, it seemed prudent to add another floor to provide space for a future expansion, said architect John Chase of EwingCole. From the beginning, some project supporters worried that the Family Court building was too small to accommodate the rising caseload.

The problem is that no one told the neighbors that Family Court could end up 15 feet taller than approved.

"I received no notice about this change, which is going to materially affect my building," complained Jeff Reinhold. His company, Reinhold Residential, owns the Metropolitan, a 1920s residence hall on 15th Street that was just renovated for high-end apartments according to exacting Historical Commission standards.

Reinhold also questioned whether the extra floor on Family Court was legal, given the Parkway zoning restrictions. He expects that the extra floor will block views of the Parkway from the Metropolitan's roof deck.

Reinhold said he didn't learn about the design change until Friday night, when a friend noticed the measure on the Art Commission's agenda. He alerted property owners near the Family Court site.

Despite neighbors' presence at Wednesday's Art Commission meeting, Chairman Moe Brooker called the vote on the height measure without allowing them to comment. The decision would have stood if Panek, who works as a federal prosecutor, had not protested.

Several commission members said they were also troubled by the rush to approval and offered a motion to overturn the vote.

Commissioner Sean Buffington noted that the board's job was to review the design of public buildings, not to rule on zoning disputes.

"We're not able to assess whether this is legal under the zoning," he said.