Home loan query

My mother is the owner of the house we are currently residing in. We want to apply for a home loan to construct an additional floor. I want to ask whether I can claim deduction for interset upto 150,000 and Principal repayment upto 1 lakh if I pay the EMIs. The loan will be taken in my mother's name but I will be paying full EMIs on her behalf. If this is not possible, can I claim the deductions mentioned above If I become the co- borrower in the loan. Please note :-In all the cases I am not the legal owner of the house.