After hours of backroom negotiations, members of City Council remained unready Monday to vote on Rebuild, the $500 million plan to remake the city's parks, recreation centers, and libraries.

For the second time in a week, members postponed a vote on the proposal, saying they needed to fine-tune an agreement with the building trades unions meant to ensure diversity on Rebuild work sites.

"We needed to stop, hold, pause until we get that information," Councilwoman Cindy Bass said. "We're not in a hurry. … It's much more important — for me, at least, and I think most of my colleagues — to get it right instead of getting it fast."

Mayor Kenney's administration hopes Council will approve the legislation before it breaks for summer recess this month. But Council has shown little urgency to rush the process, because city officials do not plan to borrow money for the project until litigation challenging the city's beverage tax is settled. Proceeds from the tax would pay back the bonds for Rebuild.

Rebuild is expected to involve renovations at 150 to 200 sites over more than five years, and is being pitched as a vehicle for broad social and economic change as well as a way to address the longstanding lack of diversity in the city's building trades.

Last week, at a heated hearing on the proposal, Rebuild executive director Nicole Westerman committed to hitting the project's 45 percent minority-participation goal in the first year, something she previously said would take several years to achieve.

Asked Monday about the unexpected pledge, Council President Darrell L. Clarke called it a "statement in the heat of the battle." Asked if it was realistic, he said he hoped so.

"This notion that goals will be reached and numbers will be reached at the end of the Rebuild process was never something any of us felt comfortable with," he said.

With the goal of hitting diversity marks quickly, Council on Monday amended the bill to expand the pool of applicants from which members of the Philadelphia Building and Construction Trades Council would commit to hiring.

Rather than just using workers from a new pre-apprenticeship program being developed as part of the Rebuild process, the unions also would be expected to tap existing pre-apprenticeship programs such as PennAssist, an initiative between the trades and the University of Pennsylvania that provides a pathway to union membership for Philadelphia public school students.

The latest draft also includes a commitment that at least half of the workers on Rebuild sites reside in Philadelphia.

Council is scheduled to reconvene its hearing on the proposal at 9 a.m. Thursday.