Very new to this forum, forgive me for any mistakes.
I am replacing the decking on an existing deck at my house, and the new decking is a composite PVC cap stock product. The old decking was cedar, and the joist spacing was 24". That is beyond spec for the new decking, so I am adding a 2x8 joist in between for 12" spacing.
The problem I'm having is that the old 2x8 joists are 7" actual width, whereas the new joists are 7.25". This causes the new joists to be proud of the old ones, including the rim joists. I don't think I can just hang them and then run the decking over uneven joists.
Has anyone seen this before? Can anyone comment on why the old joists are small? Could that just be due to shrinkage?