Creating Exposed Trusses in a Cathedral Ceiling


Reference Number: KB-00416
Last Modified: February 13, 2019

The information in this article applies to:

Chief Architect Premier



QUESTION

How can I create exposed roof trusses in a room with a cathedral ceiling?  

Exposed trusses over modern kitchen


ANSWER

When a roof truss is drawn in Chief Architect, the program locates a roof plane to define the top chords of the truss, and a ceiling plane to define the location of the bottom chord.  You can create exposed trusses by creating a ceiling to define where you want the trusses' bottom chords, drawing the trusses, and then removing the ceiling.


To set up the structure for exposed trusses

  1. Open the plan file in which you would like to create exposed roof trusses.

    Four walls that define a room

    • In this example, a simple rectangular structure is used.

    • If your plan has multiple floors, go up to the floor where you want to create exposed trusses.


  2. Using the Select Objects  tool, click in the center of the room to highlight it, then click the Open Object  edit button.


  3. On the Structure panel of the Room Specification dialog that opens, set the Rough Ceiling height to the height for the wall top plates, then click OK.

    Room Specification dialog - Structure panel - Rough Ceiling set to 109 1/8


    If all rooms on this floor have the same plate height, it is best to set the Rough Ceiling value in the Floor Defaults.

  4. Next, select Edit> Default Settings  , select the Framing category, then click Edit.


  5. In the Framing Defaults dialog:

    • On the Trusses panel, specify the desired Member Depth and Maximum Horizontal Span for your trusses, then click OK.

      Framing Defaults - Trusses panel - eight inches entered for Top Chord, Bottom Chord and Webbing

    • On the Roof panel, set the Width of the Rafter to your desired value.

      Changing the rafter width on the Roof panel of the Framing Defaults dialog

    • On the Materials panel, choose your truss material, then click OK.


  6. Staying in the Default Settings dialog, select the Roof category, then click Edit.

    • On the Structure panel, specify the desired Truss Width in the Rafter Width text field then click OK and Done to confirm the changes and close the dialogs.

      Roof Defaults dialog with eight inches set for Rafter Width on the Structure panel

      In this example, setting an 8" width will give us a square beam for the truss components.

      You can set the Rafter Width in either the Framing Defaults or the Roof Defaults. To reduce confusion, it is best to change it in both places.  


  7. Select Build> Roof> Build Roof from the menu and in the Build Roof dialog:    

    • On the Roof panel, check Build Roof Planes, Trusses (No Birdsmouth), and specify the desired Pitch, as well as any other attributes that you'd like to change at this time.

    • Click OK to close the dialog and build the roof.


  8. Depending on the type of truss that is desired, make modifications to the ceiling to produce truss bottom chords that meet your needs. For example:

    • Use the default flat ceiling to produce a standard truss:

      Standard truss with eight inch cords and webbing

    • Raise the ceiling height of a room to produce a modified truss with a raised bottom chord (make a note of the original value before doing so):

      Modified truss with eight inch cords and webbing

    • Remove the default flat ceiling and draw sloped Ceiling Planes to produce a scissor truss. More on creating scissor trusses can be found in the Related Articles section below.

      Scissor truss with eight inch cords and webbing


To draw the roof trusses

  1. Select Build> Framing> Roof Truss  from the menu, then click and drag a line over the roof to create a single roof truss.  

    A single truss drawn across two roof planes

    Note: If you receive a Question dialog stating that "The layer "Framing, Roof Trusses" is not displayed. Do you want to turn on the display of this layer in the current view?", click yes.

     
  2. Move the truss into position over a non-bearing wall either using its edit handles or by moving it using a dimension line.

    Truss is moved over the wall - dimension value of distance to wall reduced to zero
     

  3. With the first truss in place over an exterior wall, click on it to select it, then click the Multiple Copy  edit button. 


  4. Next, click the Multiple Copy Interval edit button to open the Multiple Copy dialog:

    Multiple Copy dialog with 48 inches entered for Primary Offset of All Trusses
                      
    • Specify the desired Offset Between Copies When Dragging for All Trusses and click OK.

    • When you click OK, the truss will still be selected and the Multiple Copy  edit tool will still be active.


  5. Click and drag the truss perpendicular to itself using the Move edit handle to create copies of the truss at the specified intervals.  As you drag, your cursor will display the Multiple Copy icon.

    Multiple Copy tool used to copy the trusses across the room

    • When you have the desired number of trusses, release the mouse button. 

       

To make the trusses exposed

  1. When your trusses are in place, click the Select Objects  tool, select the room below the trusses and click the Open Object  edit button. 


  2. On the Structure panel of the Room Specification dialog that opens: 

    Room Specification dialog - Structure panel - Flat Ceiling Over This Room deselected

    • Under the Ceiling heading, remove the check beside Flat Ceiling Over This Room.

    • Click OK to close the dialog and apply your changes. 


  3. Select 3D> Create Perspective View> Full Camera from the menu, then click and drag a camera arrow inside the room with the trusses above.

    Camera View of room with flat ceiling removed showing vaulted ceiling


  4. With the 3D view active, select Tools> Layer Settings> Display Options  from the menu.   


  5. In the Layer Display Options dialog:  

    Layer Display Options dialog with Framing, Roof Trusses set to Display

    • Scroll down to the "Framing, Roof Trusses" layer and click in the Disp column to place a check in that column. 

    • Click OK to close the dialog and apply your change.   

      Camera View showing bottom cord of truss as well as truss webbing


  6. If you would like the top chords of your trusses to be exposed, click on the roof planes above to select them, then click Open Object  edit button. On the General panel of the Roof Plane Specification dialog:  

    • Lock the pitch by clicking the radio button to the right of the Pitch text field.

    • Increase the Baseline Height by typing in the text field. The height that you specify may depend on the Ceiling Finish that you specified above.  For example:

      • If you specified planking, you may want roof planes that bear entirely on the trusses and should raise the Baseline Height by an amount equal to your trusses' top chord depth.

      • If you specified sheetrock, you wouldn't want the sheetrock to bear on the trusses, and might increase the Baseline Height by the top chord depth minus the sheetrock thickness.

    • You may also want to adjust the Rafter Depth value.

    • Click OK to close the dialog and apply your change.  

      Roof and ceiling raised to expose top cords of trusses