– Before the doors of President Obama's library open on Chicago's South Side, truckloads of White House archives will be shipped to a former furniture store in the northwest suburbs.

A massive volume of paperwork, electronic data and artifacts will find a temporary home at the old Plunkett Home Furnishings store in Hoffman Estates, Ill. As many as 120 employees will be brought in by the National Archives and Records Administration to sort through the material, which ultimately will be part of the Obama Presidential Center.

The National Archives employees will organize, digitize and preserve the contents of what is sometimes called the "president's attic," said John Laster, who directs the Presidential Materials Division at the agency and has toured the Hoffman Estates site.

Technically, the National Archives doesn't take legal custody of Obama's documents until 12:01 p.m. Jan. 20, 2017, after the next commander in chief takes the oath. But with an OK from the White House, the agency can begin shipping and organizing some materials well before that date, Laster said.

The materials that will wind up in the library are not just from the Oval Office, but from almost every part of the Executive Office. According to Laster, the agency already is providing "courtesy storage" for some of Obama's presidential papers in a location he declined to disclose, though archivists can't yet dig into the boxes of documents. The no-peeking rule does not apply to such artifacts as gifts from foreign leaders or haute couture gowns worn by Michelle Obama that are expected to be part of the collection.

Archivists are bracing for 200 terabytes of electronic records covering Obama's eight years in office. That's a lot — 10 terabytes was enough to hold the printed collection of the Library of Congress, according to a 2000 study by the University of California, Berkeley.

The old Plunkett's store, which was shuttered in 2009 after the housing market crashed, was leased by the government for six years for $11.3 million. The nearly 74,000 square feet of space will not be open to the public, so people will have to wait until the Presidential Center opens to lay eyes on the lode of documents and artifacts.

The center is scheduled to open in 2021, though Freedom of Information Act requests for records won't be accepted until the following year, five years after Obama's term is up. Some records will be off-limits for seven more years under the law that governs presidential records.

With 13 presidential libraries in its portfolio — facilities that cost taxpayers nearly $69 million in the year ending last Sept. 30 — the National Archives is custodian of iconic artifacts past presidents have left to history and the libraries and museums built in their honor.