Tricks of the Trade: Hip Rafters

One way I try to continue to grow as a designer is by observing my employer, co-workers, and my clients. In order to constantly learn, I must continually ask myself the following questions:

  • How do they design their projects?
  • What method do they use for time-saving shortcuts?
  • How do they arrange their days to maximize productivity?
  • How do they tackle with various problems that come up?

There isn’t a handbook that covers every single problem we might run into, so it’s important to take what we know and apply it with creative solutions.

At Gould Design, Inc. we are an extension of our clients’ design team in every possible way. As such, we must be able to adopt the design style of that particular team so that there isn’t a variance between our work and that of the in-house design staff. We simply cannot allow either the shop or the end-customer to be able to see the difference in our designs. There are often multiple ways to “skin a cat” and today I want to tell you about one I learned recently that I really like.

On California hip sets, the hipmaster or #1 hip is setback 6′ or 8′ from the wall edge (in most applications). Some kind of corner rafter is typically used, either stacked or a single rafter or a diagonal hip girder. This particular client uses a single rafter which at first glance it would seem like we would be asking for deflection troubles. The first image shows our typical California hip set with our main focus being on R01 and J02.

california-hip

Here is J02 as it comes in by default:

4-foot-jack

The R01 is a single 2×4 Corner Rafter and clear spans (from the wall to the hipmaster) and supporting the top chords of J01, J02, J11, and J12. We can see that we are having issues with deflection:

truss-shear

The solution is as simple as this. We will first remove the bearing from the top chord of J2 that is being applied to the corner rafter. I like to do this in MiTek Sapphire before importing the truss.

hip-girder-setback

We’ve adjusted J02 to remove the bearing condition at the end of the top chord. We’ve added a diagonal web with a level “seat” cut to support the corner rafter and added a point load for the corner rafter.

girder-jack-rafter

Finally, we manually add the bearing that J02 now provides the corner rafter. It runs just fine. The point load being shown is just from J12, as J02 is now supporting the rafter.

corner-rafter

We hope you’ve enjoyed this creative approach at solving this particular problem. How do you all handle corner rafter deflection issues?

Tim Hoke – Design Professional

Gould Design, Inc.