Updated 4:18 p.m.

A Philadelphia judge has ruled that the Painted Bride Art Center can’t sell its Old City home because of the building’s “irreplaceable” mosaic facade, designed by Isaiah Zagar in the 1990s.

The sale of the building at 230 Vine St. would “all but ensure the destruction of what many individuals consider to be a true treasure,” Philadelphia Orphans’ Court Judge Matthew D. Carrafiello wrote in an opinion issued Thursday.

The Bride, an arts nonprofit, went to court seeking approval of its agreement to sell the iconic building to Groom Investments. The developer, which wants to build 16 condos with parking on the site, has not come forward with any plans to preserve the Zagar mural.

But for the Bride, the sale was an attempt at staying afloat in a changing city. Old City is no longer the scrappy place for artists that it was when the organization moved into the neighborhood in 1982. The building, the group argued, had become a burden that distracted from its mission of supporting and producing art in the city. The $4.85 million in revenue from the sale would be used as an endowment to support its programming.

In his ruling, Carrafiello wrote that the move jeopardized a tradition that “goes to the core of the reason for the entity’s existence.”

Jim Moss, Zagar’s attorney, described the ruling as a victory that may even set a legal precedent in the region.

“I think it’s very significant. I’m not aware of any decisions by a court in this area where such a sale was turned down because it would result in the destruction of an important piece of artwork.”

The ruling came as a shock to Laurel Raczka, the Painted Bride’s longtime executive director. She said the nonprofit is now weighing its options, including whether to appeal.

“We believe strongly in our new vision of providing programming throughout the city, bringing our resources to communities throughout Philadelphia, but right now we haven’t made a decision of what’s next,” Raczka said.