Unpermitted Room Addition Advertising & Appraising

[Brendan Delahooke]

I am looking at buying a home that is a one bed, two bath 2,600 sqft home and adding some bedrooms. There is a very large living room that I want to build walls and create bedrooms out of to add value to the home. If I do the work unpermitted by a licensed contractor, is it illegal to advertise it based on the added bedrooms? Permit timeframes are long and I'm looking to flip the home.