The most frenzied American ritual you’ve never seen is called the “transfer of families,” a five-hour tsunami of activity that transforms President Obama’s home into President Trump’s.

“I call it organized chaos,” said Gary Walters, who choreographed several transfers of families in his 21 years as the White House chief usher.

“It’s energizing,” said Ann Stock, who saw the transfer up close as the Clintons’ social secretary, “but absolutely exhausting.”

Here’s what happens on Inauguration Day before and during those five hectic hours.

[Read related: When Donald Trump gets sworn in, the White House is in line for a decorating update]

While Barack Obama was being sworn in as the 44th president on Jan. 20, 2009, his family’s belongings were unloaded at the White House. (David Hume Kennerly/Getty Images)

Ground Floor

Main

kitchen

Map

room

China

room

Ready: (Relative) calm before chaos

The 90-plus permanent White House staffers and a few trusted contractors show up around 4 a.m. — some sleep on cots at their workstations — ready to execute the battle plan devised by the chief usher. Although this will be Chief Usher Angella Reid’s first transition, staff turnover at the residence is rare, so most of these folks have done this at least once before.

Looking back at a free-for-all

This painting depicts a rowdy crowd in the East Room of the White House on President Andrew Jackson’s Inauguration Day in 1829. (Louis S. Glanzman. Image courtesy of the White House Historical Association)

Until President John F. Kennedy’s inauguration, there was no formal process for moving a new president into the residence, said White House historian William Seale. John Adams simply left early. Thomas Jefferson stayed in the White House with the Madisons for a month after his term ended. And so many well-wishers swarmed into the White House after Andrew Jackson’s inauguration that the new president sneaked out the back to a hotel.

The kitchen staffers are among the very few who are not pulled into moving duty, because they are already scrambling to create breakfast, the traditional congressional coffee, afternoon snacks, dinner for who-knows-how-many and preparations for the next day’s social events.

(To be clear, we are talking about the residence staff, not the administrative staff. The press secretary does not make the First Family’s beds, and policy advisers do not arrange the president’s sock drawer. However, they probably will schlep their own boxes to their new offices in the East and West wings.)

Some items for the new family may be stored in out-of-the-way places on the ground floor such as the China Room, and a bit of moving work may begin early and inconspicuously, but no one wants to appear to be shooing the first family out the door.

“We always remember that the house still belongs to the current president up until the time the new person raises their hand and takes the oath,” said Reid’s immediate predecessor, Stephen Rochon, who was a Coast Guard rear admiral before arriving at the White House. Rochon said residence staffers are ferociously discreet and do not discuss politics — ever.

Looking back at a free-for-all

This painting depicts a rowdy crowd in the East Room of the White House on President Andrew Jackson’s Inauguration Day in 1829. (Louis S. Glanzman. Image courtesy of the White House Historical Association)

Until President John F. Kennedy’s inauguration, there was no formal process for moving a new president into the residence, said White House historian William Seale. John Adams simply left early. Thomas Jefferson stayed in the White House with the Madisons for a month after his term ended. And so many well-wishers swarmed into the White House after Andrew Jackson’s inauguration that the new president sneaked out the back to a hotel.

President Dwight D. Eisenhower and first lady Mamie Eisenhower say goodbye to the residence staff the day of President John F. Kennedy’s inauguration. (White House Historical Association)

First Floor

North

Portico

State

Dining

Room

Blue

Room

Set: Getting close …

Not wanting to say goodbye

Dale Haney, the White House groundskeeper, on the South Lawn with Bush family dogs Barney, left, and Spot in 2002. (Spot predated Miss Beazley.) (George W. Bush Presidential Library and Museum/NARA)

During the staff’s farewell to George W. Bush, Anita McBride, Laura Bush’s chief of staff, glanced outside. “I saw Dale Haney, the groundskeeper, and he was there with Barney and Beazley, the dogs, giving them one last walk. He said he didn’t go to the goodbye because he really finds it hard every single time. So there he was with the dogs, this sort of peaceful moment on the South Lawn. It was a reminder that the staff there really gets close to every single family, and then they are able to flip the switch with the new first family. That’s how professional they are.”

About 8:30 a.m., the staff gathers in the State Dining Room to say goodbye to the first family and give them a special gift. During President Ronald Reagan’s departure in 1989, Walters, then the chief usher, began a tradition of presenting a box made of historic White House wood that contains the flags that flew over the White House on the president’s Inauguration Day and on his last morning in office.

The moment is always bittersweet.

“President Bush was pretty much in tears when he addressed the staff,” Rochon said of the younger Bush. “As a retired military officer, I’m not supposed to be tearing up, but I did — and so did the staff.”

About an hour later comes the last official event that the outgoing president will attend in the White House, a coffee in the Blue Room that includes the incoming and outgoing vice presidents and their spouses and a congressional escort.

By 10:30 a.m, they will leave through the North Portico, and limousines will carry them to the Capitol.

Not wanting to say goodbye

Dale Haney, the White House groundskeeper, on the South Lawn with Bush family dogs Barney, left, and Spot in 2002. (Spot predated Miss Beazley.) (George W. Bush Presidential Library and Museum/NARA)

During the staff’s farewell to George W. Bush, Anita McBride, Laura Bush’s chief of staff, glanced outside. “I saw Dale Haney, the groundskeeper, and he was there with Barney and Beazley, the dogs, giving them one last walk. He said he didn’t go to the goodbye because he really finds it hard every single time. So there he was with the dogs, this sort of peaceful moment on the South Lawn. It was a reminder that the staff there really gets close to every single family, and then they are able to flip the switch with the new first family. That’s how professional they are.”

By the time President George W. Bush blew a kiss as he left the White House for the final time as president on Barack Obama’s Inauguration Day in 2009, the residence staff had sprung into action. (AP Photo/Pablo Martinez Monsivais)

Go! At 10:31 a.m., cue the crazy

Teams of workers fan out around the residence, but the most intense action occurs in the family living quarters on the second and third floors — and in one key room in the West Wing. The family has (usually) done a lot of packing ahead of time, so the staff boxes up all remaining items.

Ground Floor

South

Portico

Driveway

Truck ballet

Missing beats in the house’s heart

The Lincoln Bedroom as it looked in 1957. (AP Photo)

“During the five-hour limbo between families, the residence has an ethereal — eerie, in fact — sort of feeling that the heart is gone. … The house has no meaning any more because the president is gone. I guess a clock is a better analogy: The pendulum just stops. When the president returns, it all comes alive again.” — White House historian William Seale

The outgoing family’s moving trucks, escorted by the Secret Service and officers of the U.S.  Park Police, pull into the west side of the South Portico driveway. The incoming president’s moving trucks pull into the east side of the South Portico.

Besides moving vans, other trucks carry furniture and artwork to and from the White House warehouse in Maryland, and still others bring on-loan artwork from outside collections and new purchases from furniture stores — all secured by the Secret Service.

Commercial movers may unload their trucks, but that is as far as they get. For security reasons, only residence staffers are allowed to move items into and out of the White House, so electricians, carpenters and many other staffers become temporary movers.

“You don’t want a personal item showing up on eBay,” Rochon said.

Missing beats in the house’s heart

The Lincoln Bedroom as it looked in 1957. (AP Photo)

“During the five-hour limbo between families, the residence has an ethereal — eerie, in fact — sort of feeling that the heart is gone. … The house has no meaning any more because the president is gone. I guess a clock is a better analogy: The pendulum just stops. When the president returns, it all comes alive again.” — White House historian William Seale

Cleaning, repairing, sprucing up

After the outgoing family’s possessions have been removed, housekeepers go into overdrive, thoroughly scrubbing the residence. Rugs and window treatments are cleaned or replaced. “De-petting” will be required, especially if the new family has pet allergies.

Room temperatures and humidity levels are set to the new family’s preferences.

Plumbers, carpenters and engineers make small repairs. Electricians may install new light fixtures and run internet and TV cables. Carpenters and the curator’s staff hang new artwork. Painters may be called in for touchups.

But no major construction, painting or wallpapering happens on Inauguration Day — there just isn’t enough time.

Second Floor

Living

Room

Yellow

Oval

Room

Setting up the bedrooms

Stealthily swapping photos

The view from Marine One as the Fords say goodbye after President Richard Nixon resigned on Aug. 9, 1974. (National Archives and Records Administration)

Years before she was First Lady, Barbara Bush was impressed by the staff’s efficiency on the day President Nixon left. “After we waved goodbye to the Nixons, the pictures on the wall were all of Jerry Ford’s family,” she was quoted as saying in “The Residence: Inside the Private World of the White House.” “We were standing at the helicopter waving goodbye while they changed the pictures.”

The residence has as many as 16 bedrooms, and carpenters may convert suites to separate bedrooms or vice versa by opening or closing existing doors and wall panels. Walters said about half were reconfigured during the Reagan-to-Bush changeover to accommodate the large Bush family.

The new president’s interior decorator and a few other members of his entourage help unpack and arrange furniture.

All boxes are emptied, and clothes are placed in closets and drawers. Unlike pretty much everyone else who has ever relocated, the president will not have three unopened moving boxes sitting in the back of a closet.

The First Family’s favorite products were purchased ahead of time and will be ready for them to use — everything from mattresses and linens to shower heads and shaving cream. The first family never runs out of toilet paper.

Stealthily swapping photos

The view from Marine One as the Fords say goodbye after President Richard Nixon resigned on Aug. 9, 1974. (National Archives and Records Administration)

Years before she was First Lady, Barbara Bush was impressed by the staff’s efficiency on the day President Nixon left. “After we waved goodbye to the Nixons, the pictures on the wall were all of Jerry Ford’s family,” she was quoted as saying in “The Residence: Inside the Private World of the White House.” “We were standing at the helicopter waving goodbye while they changed the pictures.”

President Eisenhower so loved to cook — and grill, apparently — that he had a kitchen built near the Solarium. (Dwight D. Eisenhower Presidential Library and Museum/NARA)

Third Floor

Kitchen

Solarium

Stocking the rest of the residence

Respecting family traditions (even in PJs)

The White House staff adapts to families, not the other way around. (AP Photo/White House photograph courtesy of the Gerald R. Ford Library)

Former chief usher Walters said that President Ford’s longstanding tradition was to get up before Betty and bring her coffee and the morning papers so they could sit in bed and read. So  the butlers had coffee and newspapers ready for him in the kitchen every morning. “The Executive Residence changes to the desires of the family that’s coming in and how they want to live in the White House.,” Walters said. “There are ‘White House ways,’ but the White House ways are the ways of the family who is living there.” 

The family has a private kitchen and pantry on the second floor, plus a wet bar and another kitchen on the third floor. President Dwight D. Eisenhower, who spent lots of time in the Solarium, added the third-floor kitchen so that he could make soup without having to carry it upstairs. All the kitchen and pantry spaces are stocked with snacks, drinks and any other food the family has requested. (Fun fact: The president pays his own grocery bill.)

The florist puts fresh arrangements all over the house. The theater is stocked with new movies, the bowling alley gets a supply of new shoes.

Sometimes, the roof terrace is redecorated. Strategically placed plants, for instance, can create more privacy if a certain person were to want to sneak a smoke.

Respecting family traditions (even in PJs)

The White House staff adapts to families, not the other way around. (AP Photo/White House photograph courtesy of the Gerald R. Ford Library)

Former chief usher Walters said that President Ford’s longstanding tradition was to get up before Betty and bring her coffee and the morning papers so they could sit in bed and read. So  the butlers had coffee and newspapers ready for him in the kitchen every morning. “The Executive Residence changes to the desires of the family that’s coming in and how they want to live in the White House.,” Walters said. “There are ‘White House ways,’ but the White House ways are the ways of the family who is living there.” 

Former chief usher Stephen Rochon oversaw the residence and Oval Office changeover when President Obama took office. (AP Photo/J. Scott Applewhite)

Ground Floor

West

Wing

Oval

Office

East

Wing

The Oval Office: Staging history

Most parts of the East and West wings are in a state of flux on Inauguration Day as the General Services Administration (GSA), which oversees those office wings, cleans, paints and preps for the new administration’s staff. But one room has to be in impeccable shape: the Oval Office.

Wondering about the Resolute Desk?

President Obama’s Oval Office includes the Resolute Desk, which was fashioned out of timbers from the British Royal Navy ship HMS Resolute. (White House Historical Association)

A big question for history buffs is whether President Trump will use the Resolute Desk, which has been used by most presidents in one room or another since it was given to Rutherford B. Hayes by Queen Victoria in 1880. President Kennedy was the first to put it in the Oval Office; it’s the desk little John-John is peeking from in the iconic photo. Most presidents since have kept it there, including Carter, Reagan, Clinton, George W. Bush and Obama.

“That’s the first thing the president wants to see,” Walters said. “That first impression sends a message to the American people about what’s important to this president.”

That means every choice may be scrutinized for hidden meaning. A minor hubbub arose when President Obama replaced a bust of Winston Churchill in the Oval Office with a bust of the Rev. Martin Luther King Jr. Donald Trump has said he plans to bring back Britain’s wartime prime minister.

The GSA collaborates with the residence staff on this room. Some changeovers require more work than others. During Nixon’s inauguration, electricians had to remove a bank of televisions installed by media-obsessed Lyndon Johnson. When Ford took office, he had Nixon’s recording equipment and wires torn from within the walls.

All furniture, draperies and artwork will be changed — if the new president chooses to change them. The rug with the presidential seal probably will remain, at least for awhile, because new ones take so long to make.

Sometime before noon, a National Archives and Records Administration crew will sweep through all offices to collect any remaining documents from the old administration, including those on computer hard drives. They also pick up gifts from foreign leaders that may be displayed in the residence.

Wondering about the Resolute Desk?

President Obama’s Oval Office includes the Resolute Desk, which was fashioned out of timbers from the British Royal Navy ship HMS Resolute. (White House Historical Association)

A big question for history buffs is whether President Trump will use the Resolute Desk, which has been used by most presidents in one room or another since it was given to Rutherford B. Hayes by Queen Victoria in 1880. President Kennedy was the first to put it in the Oval Office; it’s the desk little John-John is peeking from in the iconic photo. Most presidents since have kept it there, including Carter, Reagan, Clinton, George W. Bush and Obama.

President Bill Clinton invited performers in the 1993 inaugural parade to see the White House. (AP Photo/Doug Mills)

Last-minute surprises

By about 2:30 p.m., the inaugural parade has begun, and the chief usher is making sure everything is perfectly in order.

This is often when the unexpected occurs, and the staff has to be ready.

During George H.W. Bush’s parade, his twin granddaughters Barbara and Jenna — who would later be White House residents themselves — became bored and wanted to enter the residence, Walters said. So the florist took them to her shop and gave them an impromptu class in floral arranging.

Stock said that during Clinton’s inaugural parade, the president felt bad for performers whose floats had broken down, so he invited them back to see his new house. They came the next day, along with thousands more people whom the gregarious president invited along the way, and the guest list swelled to 4,500 — triple the number the staff was originally expecting. Storeroom clerks had to scour the city for more hot chocolate to serve.

3:30 p.m.: Deadline

Any time between 3:30 and 5 p.m., the new first family will return to a transformed White House.

As they enter, usually through the South Portico, Chief Usher Reid will greet them and say for the first time, “Welcome to your new home, Mr. President.”