what proof do you have to have to place a mechanics lein on somebodies property? Karen, ohio

I would suggest you get counsel to review it immediately.

Generally, he files an affidavit saying: I did work. I was not paid. You are given notice and time to respond. If you do not, the lien goes on. There are strict time requirements and some very technical requirements that are beyond this forum.

You got a Notice of Lien. Your response at that time should have been a Notice to Commence Suit. I do not know if you still have time to so respond. A Notice to Commence Suit tells the lien filer to file a lawsuit within a particular period of time or remove the lien. Most contractors are very good at filing liens and not so good at actually hiring lawyers to file lawsuits so sometimes you can get the lien removed by demanding he file suit.

Please note that once the lien is in place, he can seek foreclosure to get paid. You should get legal counsel.