We own a family roofing business. What is the procedure for filing a lien if a person does not pay.

It sounds like you want to file a mechanic's lien. The procedure depends on your state's law. The easiest way to find out would be to go to the web site for your county court and see if they have any info online about how to file a mechanic's lien. If they don't have info online you should be able to get it from the county clerk's office.

You could also take the party to small claims court rather than try to place a lien on their property, because if they're not planning on moving then you're going to be sitting on a lien for quite a few years. If you win in small claims, then you could garnish their wages and recover what you've lost a little bit faster.