two surface levels on one floor

[wyskiel]

Hi, How I can make two levels of floor/surface on one floor. Half of the floor in my design room is 30 cm higher. I know I can do second level and add minus value, but then when you print you have levels on separate pages. how i can do that, plase help.

[Puybaret]

Use a 30 cm high large box to simulate the higher part of the floor.