Dropping Gable Top Chord to Accommodate Outrigger Framing

Video Transcript:

At times architectural and structural documents may call out outrigger framing at gable end conditions. Outrigger framing is typically 2x4 or 2x6 lumber that is perpendicular to the gable end. Often these two-by framing members connect to the face of the setback truss and then bear on top of the gable truss.

Be sure to verify specific spacing or loading requirements with the building designer.

In order to support the outrigger framing members, it's important that the top chord of the carrying truss matches the depth of the outrigger framing to strengthen the connection. In this example, the outrigger framing is 2x6. Additionally, the gable truss must have a dropped top chord so the outrigger framing can extend beyond the gable end.

Adjusting Common Truss Top Chord Size

We’ll start by modifying the common truss design that will be carrying the outriggers. First, we’ll select and unlink the two carrying trusses to isolate them from the other common trusses. Only the carrying trusses need to have 2x6 top chords. Next, create a new Design for one of the trusses, thereby creating a unique component. Follow this up with choosing the newly created component for the other carrying truss. We’ll modify the top chords of these carrying trusses to 2x6. To do so we will select both top chords and edit the lumber dimensions. Analyze the truss and return to layout.

Dropping the Gable Top Chord

Next, we’ll focus on the gable design where we need to drop both top chord segments. Let’s remove the wedges to get them out of our way. We’ll demonstrate two different methods.

Method 1

The first method will make use of a reference line to represent the bottom of the 2x6 outrigger framing. Create the reference line, and then change the offset from the properties.

We’ll create a new member. Adjust the location to below line. And change the member type to Top Chord. Holding the shift key, click to extend the Top chord to the left. Repeat this to extend the right side to the ridge. Next, we’ll adjust the left end of the bottom chord by shift clicking the desired cutting edges.

Method 2

Let’s turn our attention to the right side. Select the top chord and change the material to 2x6. The 2x6 represents the outrigger framing depth. Next, add a member directly below the 2x6. Change the new member type to Top Chord. Shift click to define the cutting at the ridge, and repeat at the heel. Select the bottom chord, and shift click to adjust the right side. Now, delete the original top chords and notice the vertical members are cut back to the underside of the 2x4, dropped top chord. Let’s change the material to #2, and then analyze.

Verify in 3D View

We’ll return to the layout and view our work in 3D. We can see that the Gable end is dropped for the 2x6 outrigger framing, and that the first truss in has a 2x6 top chord while the rest of the common trusses have standard 2x4 top chords.

Be sure to verify specific project requirements to ensure your truss designs align with the intent of the building designer.

We hope this video helps you on your next project requiring outrigger framing.

See you next time.