A new memorial design for the President's House, born of excitement over the site's excavation on Independence Mall in the spring and summer, will be unveiled tomorrow night at Freedom Theatre.

The modified version of an earlier plan by the design team of Kelly/Maiello Architects & Planners would allow visitors to peer down through a glass shed and view archaeological remnants of an 18th-century house once occupied by presidents and slaves.

When the memorial is completed - probably in early 2009, officials believe - it will be the first national site commemorating the lives of slaves, public officials and historians say.

The discovery of foundation footings left from the presidential seat of George Washington, who kept at least nine slaves in Philadelphia, and his successor, the antislavery John Adams, excited public interest. From April through July, more than 300,000 visitors watched from a platform at Sixth and Market Streets as archaeologists uncovered the stony arc of a great bow window designed by Washington and, just a few feet away, foundations of an underground passageway used by servants and slaves, and of the kitchen presided over by Washington's enslaved chef, Hercules.

Public officials and representatives of community groups have agreed that the new plan is the best option to embrace the archaeological findings while retaining a focus on the stories of the presidential households in general and the nine African slaves in particular.

"We think we've come up with something that does justice to the goals of the project while capturing the significance of seeing the real [archaeological] resources," said Joyce Wilkerson, Mayor Street's chief of staff. The city has managed the design process in partnership with the National Park Service.

Lawyer Michael Coard, a founder of the Avenging the Ancestors Coalition, wrote in an e-mail that he and his organization "enthusiastically support" the new design. The coalition formed several years ago to push the Park Service to acknowledge the presence of slaves at the site and to commemorate their lives.

Coard said the new design kept "the focus on the people - enslaved blacks (primarily) and free whites - who toiled and lived at the President's House." At the same time, he said, the design "effectively, creatively and ingeniously incorporates the fascinating and compelling archaeology."

In 2003, Congress directed the Park Service "to appropriately commemorate" the house and Washington's enslaved Africans who lived there.

At a public meeting at 6:30 p.m. tomorrow at Freedom Theatre, Broad and Master Streets, Kelly/Maiello will present five possibilities for the memorial, including the one preferred by officials and by a public-private task force monitoring the project. Kelly/Maiello met extensively with outside experts and community representatives while preparing the options.

The preferred plan, still in the conceptual stage, would increase the cost of the memorial from about $5.4 million - already in hand - to about $7 million. It is the least expensive of all options that would expose archaeological remnants, said architect Emanuel Kelly, leader of the design team.

Officials said they would like to raise about $10 million total, to cover additional construction costs and provide a modest endowment for maintenance, programming, and other ongoing activities.

The alternative plans include leaving the architectural remains unexposed and hewing to the Kelly/Maiello design selected in a competition last winter, enclosing the entire excavation area within a glass-walled box, creating underground viewing levels, or covering the entire site with translucent flooring.

The preferred plan leaves the first Kelly/Maiello design essentially intact. Visitors would enter a kind of fragmentary house jutting up, snaggle-toothed, from the street corner north of the Liberty Bell Center. Broad brick pillars, reminiscent of chimneys, would hold large LED screens for viewing dramatic presentations of the lives of the house's occupants.

Washington's bow window, which some architectural historians argue prefigures the oval rooms of the White House, would be suggested above ground by an arc of rectangular brick columns. This arc would mesh with the glass viewing enclosure, or vitrine, as the designers call it. The vitrine would expose the foundations of the original window, now about 12 feet below ground.

Visitors would see, about three feet from the bow window, the stone corner and walls of Hercules' kitchen and, a bit further off, the foundations of the underground passageway between the kitchen and the main house.

These archaeological remains - which demonstrate starkly the proximity of power and powerlessness, slavery and freedom, at the core of the new nation - would also be articulated in the design topside. The emotional power of the centuries-old fragments below ground would, in essence, mesh with the abstract renderings at street level.

Behind the site, at the entrance to the Liberty Bell Center, a translucent enclosure would mark where Washington quartered slaves. Archaeologists found nothing from that old structure.

Karen Warrington, a spokeswoman for U.S. Rep. Bob Brady (D., Pa.), said the design "incorporates the concerns put forward by persons who wanted to be able to speak to the archaeological findings, and I think it successfully upholds the mandate for a fitting and appropriate commemoration of the enslaved Africans."

"It's a best-case scenario."

Warrington is a member of the task force that has been reviewing the project.

Officials said the public presentation would explain why the preferred plan had been selected and other options rejected.

"Kelly/Maiello has come up with what I think is a very effective way of including the archaeology in the preexisting design," said independent historian Edward Lawler Jr., another task-force member. "The archaeology gives heft to the design. This is the truth. Anything built on top of that may be real, but [the archaeology] is real real."

Learn more about the excavation at the President's House, through video interviews, photos and articles, at http://go.philly.com/presidentshouseEndText

Contact culture writer Stephan Salisbury at 215-854-5594 or ssalisbury@phillynews.com.