There is a process for the Loan for Construction.
You have to contact the person in the bank from which you want to take the loan e.g. SBI.
They will give you the list of formalities which you should have before the application.
Once you have the file ready, you have to contact an Architect or a Civil Engineer who will give you a format with the estimate as per the layout finalized by you.
They will give you the Loan at the rate of 1500/Sq.ft
They will consider only the carpet area, not the plot area.
You have to arrange at least 10-20% from yourself as they will release their first payment after the basic structure is done.