2x12 can only span 18' with no center support on 16" centers.
You can use 2x8's up to about a 12' span. Use a beam in the middle of the 22' span under the 2x8s'. But I have never seen floor joist anything but 16" centers. This all depends on how your roof is supported though. You will need to actually calculate loads.
You can use 2x8's up to about a 12' span. Use a beam in the middle of the 22' span under the 2x8s'. But I have never seen floor joist anything but 16" centers. This all depends on how your roof is supported though. You will need to actually calculate loads.