Originally Posted by Clough
I would go and speak with the man and let him know that you are having a challenge in this situation and that he is the one who can help you with it. Saying it that way is not blaming him for the problem. Also, it is not likely to put him on the defensive.
I would then let him know what you found out by looking at the blueprints and speaking with his secretary. And, that it was understood that he wanted the garage cleaned also, but in order to do that, you would need to add the extra square feet into the agreement. Right now, he is only going to be paying for you to clean 2085 sq ft. That was the agreement. If he wants the garage cleaned, then he is going to have to pay for it.
If he was willing for you to do work based upon a verbal agreement rather than a written contract, it sounds like he trusts you. So, I think that it would be likely for him to change some things in order to get the entire job completed, that is, if he is a reasonable person. .
How do you know that he doesn't want to pay for the cleaning of the garage? He probably just forgot about the square footage of the garage and was only remembering what it is for the house. Everyone makes mistakes
Please speak with him. You can do this.