5 Now the upper rooms were narrower, for the galleries took more space from them than from the rooms on the lower and middle floors of the building.

Read Ezekiel 42:5 Using Other Translations

Now the upper chambers were shorter: for the galleries were higher than these, than the lower, and than the middlemost of the building.
Now the upper chambers were narrower, for the galleries took more away from them than from the lower and middle chambers of the building.
Each of the two upper levels of rooms was narrower than the one beneath it because the upper levels had to allow space for walkways in front of them.