Temporary Custody Time Frame

I was hoping I might get a reply from an attorney on this. I realize the average person might not have this knowledge. Are there any online attorneys to possibly find out how many years/months of temporary custody must pass before it converts to permenant custody?

I have had physical custody of my 2 boys for 5 years. No formal custody paperwork has been completed since the X did not show for court ordered mediation. He does not have any visitation paperwork. We have been unable to serve contempt paperwork on him. It is my understanding that after a certain amount of time~ my temporary custody agreement will become permenant in the State of North Carolina. Is this correct and how many years/months are required?