Is new roof deductible?

[Helen Lowery]

I have an opportunity to buy a deal, but the house needs a new roof ASAP.  We are doing a lease-option, so I won't actually be purchasing the property until 1 year from now... just sub-leasing.  I have asked the owner if he would consider replacing the roof (which is long overdue) to protect the investment over the next year until I buy.  Can someone help me work through the options here?  Is replacing the roof a deduction for him...or an expendable item that depreciates for me... or both?  What incentives can I give him to replace the roof now?