When it comes to sell your home in Oregon, in most cases, you will have to provide the seller with Property Disclosures. The buyer has five days to disapprove the disclosures. If the buyer does not receive the disclosures, the buyer may back out of the transaction up until closing. One set of questions involve remodeling: Did you remodel? Did you require a permit? Was a final inspection approved?
The City of Portland Bureau of Development Services has put out the Guide to Permits and Inspections for One and Two Family Dwellings.
It is a good primer but if you have questions as to your specific situation, ask for a consult.