Modifying Structural Transition Gables

Video Transcript:

 In this video, we are going to be creating a transition gable where the truss span changes at the rear of the structure.

Because only 4 feet of the truss is continuously bearing, it will be a structural gable requiring standard webbing and gable studs at 2 feet on-center.

Specific to transition gables, we'll be adding blocking that follows the slope of the adjacent roof plane.

Prior to modifying the truss design, we need to identify some important dimensions and reference information.

With the transition gable selected, we see that the right end of the gable extends beyond the adjacent trusses by 4 feet, which is where our sloped blocking will begin.

So, let's get to it. From the list of components click on B01-GBL-T to open it in Design Mode.

We'll begin by using reference lines to define the starting point for our sloped blocking.

Right click and select Reference line.

We will place this at four feet from the right, so click the right edge of the bearing and then holding down the shift key, move to the left and click to place it at 4 feet.

Once the reference line is placed, we can review and modify the distance as needed from the right sidebar. So, make sure it is defined as negative 4 feet.

Our trusses have a 4 and 3 sixteenths heel height and we want our sloped blocking to be a bit above that, let's say at 6 inches.

Next, let's create another reference line to represent the upper extents of our sloped blocking. Right click and select Reference line. We will add this reference line 6 inches from the bottom edge of the truss.

Click and move your mouse up and press the control button to place the line. Then confirm the 6-inch offset from the properties panel.

And for our last reference line we will right click, and select reference line. We will place this starting point from where those 2 reference lines cross, and we want this at a six 12 slope.

Again, you can confirm the direction in the properties to be at a negative 6.

There we have it.

To place our sloping members, right click, select member, and start the first member at the right side. Double click the 6 12 reference line. This will be below the line. So, right click on the member, select Geometry, and select below line.

Once we place our first member, let's take a look at it in our 3D view to make sure we have what we want.

Let's return to our truss design and add more members.

Right click, select member, double click the center line that appears. Continue adding the next one, right click, select member, and use the same center line.

Repeat by right clicking and selecting member, then double click the center line.

And for the last one, right click, select member, double click the center line.

Let’s take a quick look at this in 3D, these all look good. You can see the sloped blocking lines up with the adjacent trusses.

Next, let’s input our gable studs.

While we could input individual members at 2 feet starting from the peak, this would be quite repetitive.

Instead, we'll define our right-most gable stud and then insert the remaining verticals all at once.

Let's add our gable stud at 16 feet to the right of the peak. So, we will right click, select member, and click the centerline of the vertical web at the pitch break. Hold shift to move in increments of feet, and place the new vertical at 16 feet.

Now for the remaining gable studs.   Right click, select member, click the centerline of the vertical web again. We need to change the Quantity to 7, and then hover above the center of the newly added vertical web. You'll notice the new member placement is previewed at 2 feet on-center.

Where you click to place the members is critical. With the centerline of the right-most vertical web referenced, move your mouse vertically until it approximately aligns with the ridge. Then click to place the new verticals.

One last step here, we need to adjust these new member types to be Gable Studs.

To do this, we will start with the top member. Select W14, then go over to the properties panel and in the member type, click and select Gable Stud.

Next, click on W15, and change the member type here to Gable Stud.

We will repeat this process for W16. Then we will continue to work our way down. Select W17. And then followed by, W18.

We will do the same for the final three members select W19, W20, and W13.

Changing the member type, for each of these, from Web, to a Gable Stud.

That will do it for our newly, added gable studs.

Let's again, switch over and take a look at how this all looks in our 3D layout.

There we have it. We've can see our sloped blocking, and the gable studs for our structural, transition gable.

Moving back over to design mode. We need to analyze this truss one last time to confirm all Checks Pass. This truss is good with the changes we’ve made.

As a best practice, it's a good idea to verify the Analog Model. So, let’s click the analog icon here to view this. Notice that the sloping blocks are defined as webs and therefore are included in the analog. You can change these member types to non-structural blocks if you'd like to remove them from the analog.

Then you would analyze one last time and you'd be all set.

We hope this video has demonstrated some tools to help you on your next structural, transition gable.

Thanks for watching!