Shout out to all the CPAs out there - mort deduction retroactive

[Steve Graham]

I posted this last week.  I got one response but was hoping to corroborate.  

I did a remodel on my house 1 year ago (cost 275k). Now I am doing a cash out refi (almost 400K). I believe I can take a mortgage interest deduction on the 1st 100k no questions asked. My question is whether I can retroactively use the renovation to take the mortgage deduction on an additional 275k.

Thanks.

Steve