Ezekiel 41:6-7

6The side rooms were on three levels. Each level had 30 rooms. The temple's wall at each level was less thick than the wall below. So the wall itself held up each level of rooms. They did not have to fix the side rooms into the temple's wall.

7The side rooms at each level were wider than the rooms on the level below them, because the temple's wall was less thick. There was a set of stairs that went from the lowest level to the middle level and up to the top level.