Buying as primary residence vs investment

We have a commercial spot under contract that has a 3/1 house as well as some storage potential and a small commercial unit. In talking with the bank we are getting in house financing at 5.4% amort 30 years. My question is we plan to rent the house and use the commercial building, I told the bank it would be our primary residence but we will be doing rehab and renting. I want to be able to write off all the expenses for the rehab so I need it to be an investment property instead of primary residence. Why does it matter and will the bank care if I say it's going to be an investment property?