For my character's 'chamber room,' because he lives in a modern apartment, I imagine the walls to be solid, and the floor to be tiled. There would also be a walk-in closet where magical items and herbs and stuff are stored.
Love this interior chamber of a medieval castle. There's a high ceiling, and it's a good thing considering that there's a hearth without a proper fireplace or inglenook. The potential for smoke in the room must have been great.