Now this job will definitely require a permit from the town. You may want to stop in at town hall, go to the counter on the second floor and ask for advice. They don't bite and in fact will be very helpful.

Run don't walk from any contractor that tells you that a permit is not needed or required. The cost of the permit is marginal, it will protect you from shortcuts and shoddy workmanship that is very common these days AND having a permit will NOT increase the municipal taxes on your home.
Good luck and enjoy your new open concept.
