Open to below: stairwells and double-height spaces

Use Open to floor below for stairwells, atriums and the upper half of a double-height room.

Before you start

• At least two floors, with the room drawn on the upper one.
• Edit access to the design.

Mark a room as open

1. Switch to the upper floor and select the room (draw walls around the opening first if needed).
2. In the inspector, under Floor, turn on Open to floor below.

The lowest floor can't be opened: there's nothing below it. You don't need a matching room on the floor below.

What changes

• Plan: the floor finish is hidden and a dashed cross is drawn corner to corner, labelled "Open to below". PDF, PNG, SVG and DXF exports show the same.
• 3D: the room has no floor slab, so you see down to the floor below (turn on Floors below in the 3D toolbar).
• Areas: the room is still listed in the room schedule (marked "Open to below") but it is left out of the total net and gross floor area and out of flooring estimates. The estimate says "open-to-below voids excluded" when that applies.

Double-height rooms

For a two-storey living room, set the downstairs room's ceiling to Open (see Ceilings) and mark the room above as Open to floor below. The downstairs room's volume is then measured up to the ceiling of the floor above.