On almost all Construction-to-permanent loans we build in an interest reserve so you never have to make payments during construction.

An "interest reserve" is an escrow account in your name which is used to make interest only payments on the outstanding balance of your loan during construction.  Each month you will recieve a statement showing how much has been disbursed on your loan, the new balance and what your total debt service (interest cost) was for that month.  You will then see where that amount has been debited from your reserve and how much you have left.  If you finish early and you still have a few thousand dollars in your reserve...take it!  You may also just use it to pay down your permanent loan amount.

Most importantly, you never need to make payments on the home you are building while you are still paying for the one you live in.