ElectrospacesTrump's demolition of the East Wing of the White House reveals that the roof was actually made of concrete - not really a surprise as it was built above the bunker known as the Presidential Emergency Operations Center (PEOC)
The interior of the Presidential Emergency Operations Center (PEOC) can be seen in a series of unique photos from 9/11:
https://www.electrospaces.net/2015/09/911-inside-white-house-emergency-bunker.html
