If 5,000 square feet represents one-quarter of the second floor storage space, then the second floor has 5,000*4=<<5000*4=20000>>20,000 square feet of storage space.

Since the first floor has twice as much space as the second floor, then the first floor has 20,000*2=<<20000*2=40000>>40,000 square feet of storage space.

Altogether, when empty, the entire building has 20,000+40,000=<<20000+40000=60000>>60,000 square feet of storage space.

Since the second floor has 5,000 square feet of storage space filled with boxes, then there are 60,000-5,000=55,000 square feet of unused storage space still available in the building.

# Answer

55,000
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Bubba bought a new two-story warehouse.  When empty, the first floor of the building contains twice as much floor space for storage as the second floor.  The first items he brought into his empty building were several thousand boxes; and he put them all on the second floor, which filled one-quarter of the second floor storage space.  If the boxes used up 5,000 square feet of storage space, how many square feet of storage space is still available in the building?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
55,000
Bubba bought a new two-story warehouse.  When empty, the first floor of the building contains twice as much floor space for storage as the second floor.  The first items he brought into his empty building were several thousand boxes; and he put them all on the second floor, which filled one-quarter of the second floor storage space.  If the boxes used up 5,000 square feet of storage space, how many square feet of storage space is still available in the building?
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