Neal asks for about 500 pounds of marble. That would be ~83 liters, or a cube with 47cm size. But the block he's working on looks more like 2m x 1m x 1m.
Neal brings home a marble rock of roughly 3 cubic meters. With marble density of 2.3-2.7 g/cm3, he's staring at an 8-ton rock. Bringing a piece like that to the third floor of a residential building is not only an extremely laborious undertaking requiring a specialty crane and riggers, but would most likely collapse the floor. Not to mention attract a lot of attention.