My question involves real estate located in the State of: Illinois
My neighbor and I share a large old coach house/garage that straddles our property line. The garage sits about 2/3 on his property and 1/3 on ours. The garage has three bays and a large loft space. We use the bay that sits on our property and can access our loft space by way of a trap door. He uses to the two bays on his property and accesses the loft by a stairway. It's time to paint the building but our neighbor insists that we are responsible for half of the cost. We believe we should only pay for one third of it since we own and use only a third, but I can't find any documentation of our responsibilities in our title papers. There is mention of a "party wall agreement" drawn up in 1945 and I'm going to try to get a copy of it from our town recorder's office but I've no idea if that refers to maintenance or not. I don't particularly trust our neighbor's memory or knowledge regarding the situation since he approached us as soon as we bought the house and tried to get us to clean out years of junk that he had amassed in the loft space. He rents the house out so he isn't actually our "neighbor" so much as the landlord next door. He pretty much only rings our doorbell when he wants something from us. To complicate things, we have an easement to share the driveway to the garage. We pay 50% of the maintenance and repairs to the driveway which I understand since we use the full length of it (it sits almost completely on his property). The garage however, seems like a separate issue but I think he may not see it that way. Any experience with this particular situation?

