The President's House is broken.

That should not come as a surprise to most of the tens of thousands of visitors who have passed through the exhibition and slavery memorial on Independence Mall.

More often than not, they've been greeted by blank video screens.

In fact, since "The President's House: Freedom and Slavery in the Making of a New Nation" opened to the public in December 2010, key elements of the exhibition have not functioned properly.

The video screens, which tell much of the story of enslaved Africans associated with the site, repeatedly have shuddered and died. The large glass box that encloses archaeological remains of the house where George Washington and John Adams served most of their presidencies and where Washington held nine enslaved Africans has fogged up and leaked.

Officials at Independence National Historical Park, steward of the exhibition, say the city, as construction manager, is responsible for shepherding repairs.

City officials say they are chagrined.

"It's an embarrassment," said Gary Knappick, deputy commissioner of public property, who hastened to add that when repairs are made, the city is determined "to get it right, and get it right the first time."

Repairs may be on the way, but visitors have been complaining for months.

"People, visitors to the site, have been concerned because the videos were not operating," said Karen Warrington, director of communications for U.S. Rep. Bob Brady (D., Pa.) and a member of the committee that oversaw development and construction of the site.

The finicky screens have been swapped out, in some cases repeatedly, but replacements haven't worked any better.

The problem is highly technical, Knappick noted, but can be summarized succinctly: The President's House environment is too hot and wet for the current video configuration.

Emanuel Kelly, principal of Kelly/Maeillo Architects & Planners, designer and builder of the President's House exhibition, said the pace of repairs had been slowed by complicated warranty coverage on various parts and by less-than-enlightening responses from far-flung subcontractors. Late summer's relentless rain did not help.

He said he persisted in trying to get the original units to function, and they just as persistently refused to do so.

Different parts of the video system are covered by different warranties, and no single manufacturer could be held responsible when a screen went dark, Kelly said.

So who would be on the hook for non-warranty costs?

"Probably we are," Kelly said, adding that he didn't yet know what those costs would be.

After months of tinkering, architect, park, and city officials met in August and agreed that complete replacement of the screens seemed appropriate.

"They were giving it such a college try to make what was there work," Knappick said. The city, to nudge things along, suggested an outside evaluation, and Kelly agreed.

In the evaluation, Kelly said, "we found the design and manufacturing were flawed"; tests on how the original units would perform in the face of "water and heat were not all done before bringing these units to site."

A new test screen, made by a different manufacturer, will be installed, possibly by late November, Knappick said. If it works, all the screens will then be replaced. The new units, manufactured in California, will not sit flush with the exhibition's masonry elements, which will help prevent the electrical components from overheating.

If the demo screen works correctly, replacing all the screens will take perhaps three months, Knappick said.

The problems with leakage at the glass archaeological box, Kelly said, "are minor."

The glass began fogging as soon as the site opened, largely because of moisture within the excavated area. Dehumidification equipment seemed to be improving that situation.

Then, on July 3, the top of the box fractured, and now leaks have appeared within what is supposed to be a dry area.

Knappick said the city brought in a consultant who determined the glass fractured because of a "rare" manufacturing flaw.

The California manufacturer will ship replacement panels within the week, and Knappick said installation should be complete by mid-October.

There also have been leaks through the seals between the glass panels, which Knappick said have been repaired. Other leaks have been traced to an area near the foot of the glass box. Water has been seeping through a weatherproof barrier beneath and making its way into the excavated area below.

"We're waiting for dry weather" to repair that leak, Knappick said, adding that the repairs might be completed in the next week. Kelly added that "you need at least two days of dry weather" in order to effect the repairs, which should not be costly.

There are reports of other possible water issues inside the archaeological area, but examination of them also awaits drier weather, according to park officials.

Once the site is functioning as intended, it will be transferred completely to the care of Independence National Historical Park.

"We're doing the best we can under the conditions," Kelly said.

Contact culture writer Stephan Salisbury at 215-854-5594,, or @SPSalisbury on Twitter.