'Side chambers' in the Bible

Against the wall of the house he built extensions around the walls of the house, around both the main room (Holy Place) and the Holy of Holies; and he made side chambers all around.

The lowest story was five cubits wide, the middle was six cubits wide, and the third was seven cubits wide; for he made offsets (niches) in the walls all around on the outside of the house so that the supporting beams would not be inserted into the walls of the house.

And it was covered with cedar [as a roof] on the supporting beams that were upon the forty-five pillars, fifteen in each row.