Your opinion on language I should use in Inspection Addendum

[Christopher Hikel]

Hi all,

I'm in the process of buying my first building, a 4-plex, and we had the inspection last Friday. Everything was OK, except that water is getting into the building at the wooden joists in the basement (big no-no and potentially very expensive to solve depending on the true cause of the problem). 

Would love to get your opinions about whether I am being unreasonable in demanding that he agree to a certain wording on the inspection addendum that we will both sign.

I worded it as follows, signed it, and sent for his signature: 

He sent this bizarrely worded document for my signature:

Here is my problem with signing his document... We still have no solid proof that any of the things he says he repairs are the cause of the water getting in all along the east side of the building's basement. I am not comfortable inheriting somebody else's self-destructing four-plex, since it might be that we actually have to tear up the whole sidewalk along the east side of the building if the problem is underground. So I prefer that the wording be very specific about the outcome we are trying to achieve: source of water flow discovered and repaired."

What do you think? Am I being unreasonable in demanding that he agree to fix a problem prior to me buying, rather than doing certain tasks prior to me buying?