Deductions & credits

So, since I'm talking about my roof, would the "property plus any improvements" only apply to the roof, or do you mean the house?  For instance, if I paid $250k for the house & property and my insurance company said the damage to the roof was $15k, or which they paid $14k after deductible, and then I paid $16.5k to have the roof replaced, what would the cost basis and other numbers be?