In the trailer for Ant-Man and the Wasp, Hank Pym shrinks a multi-story building to just a few cubic feet. He then wheels it away like luggage. You can see it at the 30 second mark:
The "shrinking" technology works by removing the empty space within and between atoms. So shouldn't the building still weigh many many tons? Is there an in-universe explanation as to how Hank can take it with him?