kre84u

Don't let DreamPlan draw the floor for you automatically. With Floors selected and under "Floor Properties", Draw Mode, select "Draw Path." Then draw your entire floor in the room with the stairs. Draw around the opening you want to leave. You could have some problems with drawing your floor if your walls are not placed just right, but it's doable. Don't assume, because you hit an error, that you can't do it. You may need to temporarily delete some interior walls.