Crazy and Complicated Truss Designs – Part 8

Crazy and Complicated Truss Designs – Part 8

As truss design professionals, we design a wide variety of truss systems. This ranges from the simple garage to 10,000 sq. ft. residences to multi story commercial buildings. Every job is unique and many have some interesting and challenging truss designs to contend with. I recently had a couple of jobs that fall into that category that I wanted to share with you.

Both are residential projects each with their own challenges.


At first glance this one doesn’t look too crazy. We have some piggybacked vaulted trusses running through the center that have to be run at 12” o.c.


When you look at the trusses on the ends of the house, things get interesting. Exterior walls are ICF. The gables on the front and back of house both have vault ceilings. Based on the floor framing and interior bearing available, the trusses need to run front to back as shown without any girders etc.


This gives us some interesting truss profiles. Fortunately there is an interior bearing running though the center of the house to use. Otherwise, this design would most likely not work. Or, if it did, it would be a multi-ply situation. Due to the profile and the ceiling conditions, I cannot even make it a piggyback without leaving a ton of field framing. At nearly 15’ tall vertically, I have to rely on the shop team to stack them properly on the truck for shipment to the job site.


Trusses are top chord bearing at the sloped exterior ICF walls with top chord extended for outlookers! Funky for sure!!!

The second one I want to share with you is a larger residence that has:

  • A 15/12 pitch
  • Flat roofs
  • Attic trusses
  • Vaulted ceilings
  • Skylights
  • Multi-step trayed ceilings.

The truss profiles don’t get quite as outside the box as the first one, but there are some that could qualify for a non- typical design. Here we go, are you ready?


There is a large skylight opening in the center of the main house as well as trayed ceilings. Add in the need for some girders to support vaulted ceilings and sub-girders around the skylight and you get a hefty 3-ply girder truss.


Trusses tying into sub girders include trayed ceilings as well.


Attic trusses get involved as you move towards the garage. Fortunately, there are some interior bearings to help with the larger room width required. Trusses still have to be spaced at 16” o.c. though!


These types of jobs certainly keep things interesting and can stretch and sharpen your design skills. They provide some good challenges for a designer and it is always a great sense of accomplishment when you can complete designs such as these.

Please check back for more posts on this subject – there will always be those crazy and complicated designs out there. Let us know any unique situations you may have encountered. We are happy to entertain guest bloggers!

Look forward to hearing from you.

View Part 1 in this series here.

View Part 2 in this series here.

View Part 3 in this series here.

View Part 4 in this series here.

View Part 5 in this series here.

View Part 6 in this series here.

View Part 7 in this series here.

Stay tuned for Part 9.

Bill Hoover – Design Manager

Gould Design, Inc.