Ezekiel 42:5,6

‘Now the upper chambers were smaller, for the galleries took away from these, more than from the lower and middlemost in the building. For they were in three storeys, and they did not have pillars like the pillars of the courts. Therefore the uppermost was set back more than the lowest and the middlemost from the ground.'

We do not know the meaning of the technical word translated ‘galleries' which makes exactness difficult here, but the main point is clear, that there were three storeys and the top one was set back a little. Pillars are not mentioned elsewhere (the pillars in front of the sanctuary did not support anything) so this clearly refers to supporting pillars not yet mentioned. It possibly means the outer supporting walls of the side-chambers in the inner court (Ezekiel 41:6).