: HOUSE BUILDING
We are now ready for the ceiling joists, which are, usually, 2" × 6", unless there is an upper floor. These are laid 16 inches apart from center to center, preferably parallel with the floor joist.
It should be borne in mind that the ceiling joist must always be put on with reference to the roof.
Thus, in Fig. 232, the ceiling joists (A) have their ends resting on the plate (B), so that the rafters are in line with the joists.