Would it be possible to allow building damage but disable pvp player damage with a ruleset? I couldnt see if there was a flag that would work with this. 

it's possible, but not recommended. if someone is being raided and they can't defend their base then what will they do? it seems this idea would only serve to annoy them. they'll either quit the server or create more work for you, no?

set defaultAllowDamage to true. this will enable ALL damage by default that isn't blocked by a rule. so you will need to create rules to block damage, rather than the suggested method of setting defaultAllowDamage to false and adding rules that allow damage. in your specific case it should be the former, as creating rules to allow damage to buildings would require significantally more time, bloat the config, and ultimately hurt performance as a result

we plan on using this in a very small zone. We have the bank heist plugin and basically true pve stops destruction of the bank vault door the area won't be buildable for players. I agree this would be a crazy idea accross the whole map xD. I will give that a try thank you! 

well if thats the case then you should create a zone using Zone Manager and exclude it in truepve :p

That's exactly what we did actually XD the only issue is players can kill each other in there. 

use the PvpGod flag then. but i hear it isn't working. so someone will need to let the dev know

Yup it's not we tried that too it also blocks pve damage. I'll report it to the dev.