Adjusting Roofs Over Alcoves

Reference Number: KB-00425
Last Modified: July 21, 2021

The information in this article applies to:

Home Designer Professional or Home Designer Architectural or HomeDesigner Suite


I have an alcove (a depression into  an otherwise straight exterior wall) in the plan, and I want the roof to extend across it as if there was a wall there, but it is jogging in the roof line.  How can I make the roof extend over this area?


Alcove allowances can be set in the Build Roof dialog.

To create a basic plan

  1. In a new plan, select Build> Wall> Straight Exterior Wall, then click and drag out a basic structure, as shown in the image below.

    Floor plan view of building with a 3’ alcove and a second alcove measuring 2’ 11”

    For the purposes of this example, two alcoves are used, one which is 3' and one which is 2' 11".

To set the Minimum Alcove value

  1. Select Build> Roof> Build Roof .

  2. On the Roof panel, note the Minimum Alcove Size, and click OK.

    Build Roof dialog showing 36” entered for Minimum Alcove Size on Roof panel

    Any alcove less than the specified width is treated as though the  exterior wall continues straight across. Alcoves that measure wider than this value are not roofed over; they cause a change in roof planes.

  3. An example showing this difference:

    Floor plan view of building showing roof planes that differ over the two different alcoves

    If Min Alcove is 36", a 36" wide alcove requires a change in the roof line. Each wall of the alcove has an eave. On the right, the alcove is less than the 36" minimum, so the roof  passes right over it.