Most ceilings are separate segments, and not part of a room. I believe when you create a room, FPSC adds another floor above by default, not a ceiling. If you want to change the height of a ceiling, the line would look something like this in the ceilings FPE:
offy0 = -52
You have to change that to a larger negative number to bring the ceiling down. The reason for this is that the meshes are made in the center of the editor, or half way between the floor and ceiling. The floor mesh is made on the current level, and the ceiling mesh is made on the level above. Therefore, to make the floor or ceiling align properly, you have to move them down about 50, depending on the size of the mesh.
Change that to a larger negative number to bring the ceiling down. A -100 would bring the ceiling about half way down the wall. Start with that and correct it from there.
Brian.