Rooms in dreams, much like in waking life, are a way to compartmentalize aspects of our lives.
We undertake certain tasks in certain rooms, for instance we sleep in a bedroom, work in an office and cook in a kitchen.
In dreams different types of rooms represent different aspects of our subconscious, or symbolize thoughts connected with whatever we connect that type of room with in waking life.
So, for instance, a kitchen in a dream may represent sustenance, cooking and eating, or even family gatherings – depending on how you use your kitchen in waking life.
Furthermore, the state of the room in your dream can tell you something about the message it is trying to convey, i.e. kitchen dreams may be telling you to eat more or eat less, or eat differently, depending on how it appears in your dream.
Discovering a new room in your dream could represent discovering a new part of your subconscious, a new aspect of yourself that you haven’t explored before, an aspect that your subconscious thinks that you should explore.