In 1949, President Harry Truman trashed the White House. More specifically, he gutted it, bringing in workers to rip out nearly every interior wall, floor, and all the plumbing and wiring that had been installed bit-by-bit since 1800. Truman had good cause to tear out the White House's innards, though--the building was in such disrepair that it was nearly ready to be condemned. There were only two options: Demolish the entire structure and start from scratch, or shore up the walls, gut the interior and rebuild the classic building from the inside.
Kottke picked up on a story from The National Journal about Truman's renovation efforts. In the fall of 1948, someone discovered the ornately detailed ceiling in the East Room was sagging by half a foot. A $50,000 survey by Congress then discovered something worse: the bricks holding up the grand staircase (apparently purchased secondhand) were disintegrating. The plumbing was a patchwork mess. The best quote from an old New York Times article claims that the third floor was "an outstanding example of a fire trap."
Congress was ready to condemn the place, but Truman argued for its historical significance and asked for $5,400,000 for its restoration. World War II was over. Why not?
Now comes the cool part: Seeing what the White House looked like between 1950 and 1952, as workers emptied the building and slowly put it back together. The US National Archive's Flickr account has several pages of photos taken during the construction, and some of them are amazing.
There's much more to the history of the White House, of course. This wasn't the first time its interior had been reconstructed--in the War of 1812, British troops looted the White House and burned everything but the exterior walls. Truman had a balcony added in 1948, and soon after engineers investigated the building and discovered that it was near collapse. That balcony hadn't helped, and neither had the earlier addition of a steel third floor. Years of drilling through wooden supports to add wiring had weakened the entire structure. It's incredible that the whole building was still supported by a wooden frame.
The construction addressed that issue, explains the White House Museum:
"The mansion was then rebuilt using concrete and steel beams in place of its original wooden joists. Some modifications were made, with the most obvious being the repositioning of the grand staircase to open into the Entrance Hall, rather than the Cross Hall. ...
One special consideration was the East Sitting Hall. The higher ceiling in the East Room raised the east rooms about three feet in the original house...With the use of steel construction, Architect Lorenzo Winslow managed to reduce the difference to less than one foot."
The construction also added some modern amenities like air conditioning and an underground bomb shelter. And the construction effort was, in itself, a bit of a modern marvel. Workers had to cut apart and reassemble a bulldozer to get it inside the building (Truman wouldn't let them cut a big enough hole in the wall to fit it through). When everything had been ripped from its interior, the White House was nothing but an empty cavernous space measuring 165 feet long, 85 feet wide, and 70-80 feet high.