Ezekiel 41:5-10, 11

He then measured the wall of the temple as six cubits thick. There were side rooms all around the temple that were each four cubits wide. And there were three levels of the side rooms, with thirty rooms on each floor. All around the wall of the temple were ledges that served as supports for the side rooms so that they did not have to be attached to the temple wall for support. The rooms were right up to the temple walls. The width of the side rooms increased, floor by floor, because the width of the temple increased as it got higher, from the lowest level through the middle level to the top level. Then I looked down and saw that the temple stood on a raised platform that surrounded it. The platform was a full measuring reed high (six cubits) and provided a foundation for the side rooms. The outer wall of the side rooms was five cubits thick. On the raised platform there was a terrace all around the side rooms of the temple. It was twenty cubits between the edge of the platform and the rooms for the priests.

And the doors of the side rooms faced an open area, one door toward the north and one door toward the south. The width of the open area was five cubits wide all around.