Creating Exposed Trusses in a Cathedral Ceiling


Reference Number: KB-00416
Last Modified: February 24, 2017

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.



    • 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. To set the wall plate height for this room use the Select Objects  tool and click in the center of the room to highlight it. Next click Open Object  to open the Room's Specification.


  3. On the Structure panel of the Room Specification dialog set the Rough Ceiling (E) height to the height for the wall top plates and click OK.



    *for this article the default value 109 1/8" is used.

    If all rooms on this floor have the same plate height it is best to set the Rough Ceiling value in the Current Floor defaults instead (Edit> Default Settings, Floors and Rooms> Current Floor).


  4. Next, from the Menu select Edit> Default Settings. Select the Framing category and then click Edit.


  5. In the Framing Defaults dialog:

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



      *In this example, the Member Depth values are set at 8" and the Maximum Horizontal Span values are unchanged.





    • On the Roof panel of the Framing Defaults, you can set the width of the Rafter to give us an 8" by  8" beam look.

    • On the Materials panel, choose your truss material.



  6. Next, in the Default Settings dialog choose Roof and click Edit.

    • On the Structure panel, specify the desired Truss Width in the Rafter Width text field then click OK on the Roof Defaults dialog and Done on the Default Settings dialog.  In our example, setting an eight inch 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. In the Build Roof dialog:    

    • Check Build Roof Planes on the Roof panel.

    • Also on the Roof panel, check Trusses (No Birdsmouth)

    • Specify the desired Pitch and other attributes of the roof

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


  8. Depending on the type of truss 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:



    • 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):



    • 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 at the bottom of this article.




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.  



    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.


     

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

    • In Home Designer Pro, use the Transform/Replicate Object  edit tool to make copies of the trusses.


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


                      
    • Specify the desired Offsets 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.



    • 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: 



    • Under the Ceiling heading, remove the checkmark beside 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.




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


  5. In the Layer Display Options dialog:  



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

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




  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.