Ezekiel 41:6-7

6The side chambers were in three stories, one above the other, thirty in each story. There were offsets in the wall all around to serve as supports for the side chambers, so that the supports were not in the wall of the temple.

7The side chambers surrounding the temple were wider at each successive story; for the structure surrounding the temple went up story by story all around the temple. For this reason the width of the temple increased as it went up, and one went up from the lowest story to the highest by the way of the middle story.