Joining a Barrel Roof to a Flat Roof Plane

Reference Number: KB-00684
Last Modified: July 20, 2021

The information in this article applies to:

Chief Architect Premier or Chief Architect Interiors


I would like to join a barrel roof to a flat gable roof. How is this accomplished?
exterior of custom home with barrel roofs and arched curve dormers


An almost endless variety of roof combinations is possible using the manual and automatic roof tools in Chief Architect.

To create curved and flat roof planes

  1. Draw the walls of a structure with a bump-out in a clockwise fashion.  


  2. Specify each of the three gable walls (marked in yellow in the image below) as Full Gable Wall on the Roof panel of the Wall Specification dialog.  

    • Walls can be group-selected by selecting one, then holding down the Shift key to select additional walls.  

    • With multiple walls selected, click the Open Object  edit button to open the Wall Specification dialog and edit them all at one time.  

  3. Select Build> Roof> Build Roof  to display the Build Roof dialog.  

    • Place a check in the box beside Build Roof Planes.  

    • Click OK to close the dialog and build an automatic double gable roof.  

  4. Now either the small roof section at the front, or the large roof section over the main part of the structure, can now be turned into a barrel roof and joined to the other.

    To make the front section curved:  

    • Select both front roof planes using the Shift + click method used in step 2 above.

    • Click the Open Object  edit button to open the Roof Plane Specification dialog.  

  5. In the lower left corner of General panel, place a check in the box beside Curved Roof, which will enable the options directly below it.  

    • Specify the Angle at ridge to be 0.  

    • Press the Tab key on your keyboard to apply this change without closing the dialog and notice that both the Angle at eave and Radius to roof structure values adjust to the change.  

  6. Click the OK button to close the dialog.

  7. To view your new curved roof planes, select 3D> Create Perspective View> Perspective Full Overview .  

    • Use the arrow keys on your keyboard to view the structure from different angles.  

    • As you view the structure from the side, a gap between the flat and curved roof planes comes into view.  


To join the roof planes:

  1. This problem is easily corrected using the Join Roof Planes  edit tool. Return to floor plan view and click on one of the front roof planes near the edge adjacent to the flat roof plane to select it and display its edit handles.  

  2. Click on the edit handle that displays on the edge where you clicked and drag it into the flat roof plane, so that the two edges that you would like to join are clearly distinguishable.  

  3. With the curved roof plane still selected, click the Join Roof Planes  edit button and then click on the flat roof plane close to the edge that you wish to join to. The roof edges will move, joining at the most appropriate location.  

  4. Repeat this process with the other curved roof plane, and then select 3D> Create Perspective View> Perspective Full Overview  to confirm that your roof planes now join properly.

The process for creating a barrel roof over the main section of the structure instead of the front section is almost identical to the one described above: group-select the roof planes; specify them as curved; and then use the Join Roof Planes  edit tool to properly join the roof plane edges.  

Note: The above procedure can be used to join curved roof planes to any style roof with flat roof planes, not just gable roofs.