Specifying Different Roof Overhangs on Different Walls

Reference Number: KB-00077
Last Modified: July 21, 2021

The information in this article applies to:

Home Designer Professional or Home Designer Architectural or HomeDesigner Suite


How can I make a roof that has different overhangs on different sides?

Camera view of house with extended roof over front door


When Roofs are automatically generated, a roof plane is created over each exterior wall, following the settings in the Build Roof dialog. However, there are times when you may want create a roof that the default settings are unable to automatically generate. In the Build Roof dialog, you will notice a check box for Auto Rebuild Roofs. When this is turned on, any changes made to the position of an exterior wall or to its roof directives will prompt the roof to regenerate to reflect these changes. Knowing how the program operates allows us to manipulate the tools to create what we want.

We know that roof planes build over exterior walls and we know that the build roof dialog has a setting for overhang, but what if we want different overhangs on different roof planes? This is when we want to use temporary walls to generate the roof planes. Once we have the roof perfect we can turn off Auto Rebuild Roofs and delete the temporary walls. In this article we will cover how to make overhangs of various depths using temporary walls.

This tutorial starts with a 20' by 20' structure.

It is also possible to specify the overhang on a wall-by-wall basis by modifying the Overhang setting on the Roof panel of the Wall Specification dialog.

To create a roof

  1. First, we want to specify the default overhang to be the smallest overhang we plan on having in our plan. We do this by clicking on Build> Roof> Build Roof to open the Build Roof dialog.

  2. In the Specifications section of the Roof panel, we will specify the overhang for Eave and Gable sides.

    Build Roof dialog with Auto Rebuild Roofs selected and 9” set for Eave Overhang and Gable Overhang

    • In this example 9" is used for both.

    • Make sure that Auto Rebuild Roofs has a checkmark enabling this feature.

    • Click the OK button.

  3. Next, use invisible walls or room divider walls to delineate where the roof overhangs differ from the default.

  4. Click Build> Wall> Room Divider , then click and drag to create room divider lines for the areas where where the overhangs are different. It doesn't have to be exact right now, refinements will be made later in the design.

    Floor plan view showing Room Divider walls being drawn

    Notice that when you connect the Room Divider Lines to the existing structure, the Auto Rebuild Roofs feature automatically updates the roof structure to cover those lines. Within this overhang area, you will see a room form. Click on Select Objects and then double-click within the room to open the Room Specification dialog box.

  5. Within Room Specification, you will need to make the following changes:

    • Click on the General panel and change the Room Type to Open Below.

    • Next click on the Structure panel and remove the checkmark in the Flat Ceiling Over This Room check box.

      Room Specification dialog with Flat Ceiling Over This Room option deselected and Use Soffit Surface for Ceiling option selected

    • Place a new checkmark in the Use Soffit Surface for Ceiling check box, and click the OK button. Once you close the Room Specification dialog box, you will notice that the Room Divider lines have converted to Invisible Walls.

  6. Use CAD> Dimensions> End to End Dimension  to precisely place the walls.

    • The default overhang was set to 9" and this is measured from the roof baseline, which is the outside edge of the framing layer.

    • Add the thickness of  the invisible wall and the space between the invisible wall and the primary wall to determine the overhang depth.

      Floor plan view show wall being moved until the dimension value shows correct overhang value

      End to End dimensions were used in this image to show the overall depth of the overhang.

  7. When the roof is correct click on Build> Roof> Build Roof  to open the Build Roof dialog again.

  8. Uncheck Auto Rebuild Roofs and click OK.

    Build Roof dialog with Auto Rebuild Roofs deselected

  9. Delete the invisible walls.

    Floor plan view with new roof planes and Room Divider walls removed

With Auto Rebuild Roofs turned off your roof will not regenerate if you make changes to the walls. You should not turn Auto Rebuild Roofs off until you are confident that the roof is perfect. If you Rebuild the roof without the temporary walls in place, the roof planes will generate over the exterior walls with the default overhang.

To specify different overhangs for different walls in the Wall Specification dialog

  1. Click on the wall that supports the overhang that needs to change.

  2. Click on the Open Object edit tool to display the Wall Specification dialog.

  3. In the Wall Specification dialog click on the Roof Panel.

  4. Specify the desired overhang for that wall then press OK.

    Wall Specification dialog showing 18” for Overhang Length on Roof panel

  5. If Auto Rebuild Roofs is turned on you will see the change right away.

    If Auto Rebuild Roofs is turned off, it will be necessary to tell the program to build roof planes.

    For Architectural, Suite, Interiors, and Essentials click Build> Roof> Build Roof and click OK.

    For Home Designer Pro click Build> Roof> Build Roof  to open the Build Roof dialog.

    Build Roof dialog showing Build Roof Planes selected

  6. Place a checkmark in the Build Roof Planes check box, and then click OK.