The roof of the attached residence in our duplex is leaking into our house. Their house is up for sale. We have verbally contacted the owner and realtor with no action taken.
I take it you are a tenant in one house that is part of a duplex. Correct? I'm curious why you would call the owner's realtor, but that's not really important.
We want to document these conversations have taken place with a written letter. What needs to be included in the letter for legal evidence?
Not sure I entirely understand the question. If you write a letter, it will be evidence of its contents (in other words, a copy, accompanied by your testimony, would be admissible evidence that you notified the recipient of whatever is in the letter). However, if it were offered to prove the truth of the matters contained in the letter, it would be inadmissible hearsay.