Rookie Homeowner

Minor complications today, as my neighbor has expressed reluctance to sigin the formal agreement for my contractor to dig close to the property line. The agreement was drawn up by my contractor to protect himself since neither myself nor my neighbor really knows where the official property line is. After talked with the nieghbor, he said it was fine to proceed, but now that I ask him to sign his name to it, he refuses.

I'm afraid I might need to hire a surveyist to be 100% sure it's all on my property.