One Size Doesn’t Fit All: Why Every Truss Needs a Purpose-Built Design
Trusses might look the same from a distance, but once you start breaking down what a building needs, it becomes obvious that one size never fits all. At Truss Components of Washington, we see firsthand how profile, span, pitch, and even site conditions all factor into what makes the right truss for the job.
Span: The Starting Point
Let’s start with something simple: span. Say you’re building something 24 feet wide. A 24-foot truss will work. But a 30-foot truss? That’s not going to fit unless it’s been specifically designed to cantilever 6 feet off one side. That span is everything. It dictates how the truss supports the structure and interacts with other components of the building. If your span’s off, everything else will be too.
Shape: It’s Not Just About Triangles
The shape of the truss is another big reason there’s no one-size-fits-all solution. Most people are familiar with standard gable trusses, but if you’ve got a hip roof or a vaulted ceiling, those gables won’t cut it. A hip roof calls for flat-top trusses and a completely different configuration. Vaulted ceilings add volume and aesthetic appeal inside, but they change the entire design of the truss. A flat ceiling truss won’t create the space you're aiming for. Matching the shape of the truss to the shape of the building isn’t optional—it’s essential.
Pitch: A Small Number with a Big Impact
Pitch defines the slope of your roof, and that can range anywhere from a low-slope 2:12 to a steep 12:12. Matching the pitch is critical. Even if every other measurement matches up, if the pitch is off, the roofline will be inconsistent and won’t line up with existing structures or visual expectations. Especially in additions or renovations, the pitch has to match exactly to create a seamless transition.
Overhang: The Details That Protect Your Foundation
You’d be surprised how many people overlook the overhang. It might seem like a minor detail, but it plays a key role in protecting the building. Overhangs push water away from the foundation, preventing erosion and moisture problems. There are several styles: open rafter, cantilevered, or no overhang at all. If someone wants a cantilevered look and gets a truss with an open rafter detail, it’s not going to look right, and it won’t function as needed.
Truss Placement in a System: The Bigger Picture
Now let’s zoom out. Every truss plays a specific role in the entire system. Take a simple layout with gable ends. Those gable trusses are built to carry siding and include vertical studs for support. Somewhere in the middle, there’s likely a girder truss. This one’s responsible for carrying the weight of multiple other trusses that land into it. And in hip roof designs, you’ve got valleys and ridges that call for additional girders and complex load paths. Each truss is more than its profile. It's part of a network that distributes weight and shapes the building.
Site Conditions: Where You Build Matters
Even with the right span, shape, and pitch, the actual site conditions can completely change what’s required. Trusses built for areas with minimal snow won’t hold up in high-elevation zones that deal with heavy snow loads. Similarly, a truss made for interior, low-wind environments isn’t going to cut it for coastal regions where wind loads are significantly higher. Site conditions dictate the strength, material, and configuration required. It’s why custom design matters.
Stock Trusses: Proceed with Caution
We know it’s tempting to go with pre-built trusses. For common sizes (24, 30, or 36 feet), suppliers may keep these on hand for fast projects. But even with a perfect match on paper, you need to confirm that those trusses were designed for your specific location. Just because the size looks right doesn’t mean it’ll hold up to your site’s wind or snow loads. Double-check before you install.
Final Thought: Custom Trusses for a Custom Build
Every building is different. The span, the shape, the pitch, the overhang, the site, it all plays into what kind of truss is needed. There’s no shortcut, and there’s no such thing as a one-size-fits-all truss. When you want the structure to last and you want it to look right, you’ve got to design for the job at hand. That’s exactly what we do at Truss Components of Washington.
