Do you need to replace tar paper when using a tile roof in California?

Question:The original cedar-shake roof cracked when damaged by rain. I want to know if you can replace the roof (tile) without first removing and reapplying new tar paper. We need to know what the legalities are with roofing in California.

Any references would be great. Thank you.

Answers:
The roofing felt is actually the waterproof part of the roof. The part you see is just the sun shield. If you remove the shakes, you will certainly damage the roofing felt and have to replace it before putting any roof on top of it.