Creating an Open Below Room

Reference Number: KB-00078
Last Modified: July 15, 2021

The information in this article applies to:

Chief Architect Premier or Chief Architect Interiors


I want to create an opening or a hole to a lower floor, such as in a grand entry, loft, balcony, mezzanine or elevator shaft situation, but I don't know how to get rid of the floor in this area. How do I accomplish this task?

Timber frame structure with an open entryway


The Open Below room type is useful when you want to create an area open to the floor below it, such as for a manually created stairwell.

To create an open below room

  1. Define the area you wish to create an opening in by using any combination of the various wall tools, such as a Straight Railing .

    If you don't want any walls or railings, use the Room Divider  tool instead.

    Second floor with a railing in the middle

    In this example, we created a 20' x 30' structure, generated an additional floor level, and placed a straight railing in the middle of the second floor.

  2. Using the Select Objects  tool, select a room, then click on the Open Object  edit button to display the Room Specification dialog.

  3. On the General panel, select Open Below from the Room Type drop-down menu.

    Open Below option chosen from the Room Type drop-down menu on the General panel of the Room Specification dialog.

  4. Click OK to confirm the change, and notice that the room label will reflect the open below room type that was chosen.

    Open Below room type specified.

  5. Take a Camera view to see the results.

    Full Camera view showing an open below room