Thinking about using a Double Howe truss for your next building project?
You’re not alone. Many builders, designers, and homeowners turn to this truss style when they need something that’s strong, balanced, and easy to work with.
So, is it the right choice for you?
If your goal is solid roof support across a wide span, even load distribution, and a design that’s both practical and time-tested, the Double Howe truss design could be exactly what you need.
In this guide, we’ll walk you through everything: how the truss works, how to design one correctly, where it performs best, and what to consider before using it in your structure.
By the end, you’ll have a clear, confident understanding of whether this truss fits your project and how to make the most of its design.
Table of Contents
| 1. | Understanding the Double Howe Truss |
| 2. | How to Design a Double Howe Truss Step-by-Step |
| 3. | Advantages and Disadvantages of the Double Howe Truss |
| 4. | Double Howe Truss Dimensions and Load Considerations |
| 5. | Single vs Double Howe Truss: What’s the Difference? |
| 6. | Double Howe Truss Use Cases and Design Details |
| 7. | Final Thoughts |
| 8. | FAQs |
Understanding the Double Howe Truss
The Double Howe truss is a structural design often used in roofs and bridges that require strong support over wide spans. It expands on the standard Howe truss by adding a second set of diagonal tension members, increasing strength and stability at the center.
You might be thinking, what makes it different from a standard Howe truss?
The key difference lies in the number of panels and support lines.
The Double Howe truss includes an extra set of diagonal members, creating two opposing systems that reinforce the center and improve overall strength. This makes it ideal for larger spans that need more support in the middle.
This mirrored layout improves load distribution and reduces stress on individual members. It is a wise solution when you require more than basic support but still want a straightforward design.
Reminder: The strength of a Double Howe truss lies in its symmetry. It’s not just more material; it’s better engineering.
How to Design a Double Howe Truss Step-by-Step
Not sure where to start with designing a Double Howe truss? Good news. The process is more approachable than you might think.
Whether you’re working on a class project, a construction plan, or just brushing up on truss design, the steps below break it down clearly.
Here’s how to go from concept to calculation:
| Design Step | What to Do | Why It Matters | Helpful Reminder |
| 1. Span and Load | Measure the width to be covered and calculate the total load | Sets the foundation for safe, effective truss design | Tip: Use local building codes to estimate live load requirements |
| 2. Height & Panel Points | Choose truss height (1/4 to 1/6 of span) and number of joints | Influences structural shape and load distribution | Reminder: More joints = better load spread but more complexity |
| 3. Calculation Method | Decide between manual analysis or software tools like SAP2000 and STAAD.Pro, or SkyCiv | Affects precision, efficiency, and learning value | Insight: Understanding manual methods helps catch software mistakes |
| 4. Material Selection | Choose between wood or steel | Impacts cost, weight, and structural strength | Important: Always match material type to your load and environment |
| 5. Force Analysis | Analyze each member for tension and compression | Ensures stability, reduces risk of failure, and optimizes material usage | Tip: Double-check forces at support joints and center panels |
Advantages and Disadvantages of the Double Howe Truss
Should you use a Double Howe truss for your structure?
If your project needs wide-span coverage with strong center support, the Double Howe truss is a dependable choice.
However, like any structural system, it comes with both strengths and limitations that are important to consider before committing.
Below is a breakdown of its key advantages and disadvantages to help you decide if it’s the right fit.
Advantages of the Double Howe Truss
- Supports longer spans: The dual diagonal configuration provides excellent support for structures that require wide open areas. It performs well in buildings that need to span 40 to 70 feet without interior columns.
- Strong midsection and balanced load distribution: The mirrored layout of diagonal members helps distribute loads evenly across the entire span. This reduces localized stress and helps prevent structural deformation over time.
- Ideal for large buildings and industrial use: The Double Howe truss is widely used in agricultural buildings, storage facilities, industrial workshops, and warehouses where roof strength and open space are essential.
Tip: This design is especially effective in regions with heavy snow or wind loads due to its reinforced central section and symmetrical layout.
Disadvantages of the Double Howe Truss
- Increased material requirement: Because it includes more diagonal and vertical members, this truss uses more lumber or steel than simpler alternatives. This can raise the overall project cost.
- More complex to fabricate and assemble: Designing and constructing a Double Howe truss requires greater precision and planning. The additional joints and intersections add time to both fabrication and installation.
- Limited architectural flexibility: The design is focused on function rather than appearance. It is rarely used in exposed interiors or decorative architecture due to its straightforward structural layout.
Note: If your design goal includes visible framing or modern aesthetics, consider other truss types that offer more visual appeal and customization.
Double Howe Truss Dimensions and Load Considerations
Trying to figure out the right size for your Double Howe truss?
Well, the exact measurements can vary based on your project and location; there are general dimension ranges that most builders follow for safe and efficient design.
Here’s what you need to know.
Typical Dimensions
- Span: Double Howe trusses are commonly used for spans between 30 and 70 feet. This makes them ideal for wide buildings that require clear, open space beneath the roof.
- Height: Truss height often falls between one-fourth and one-sixth of the overall span. Maintaining this ratio helps keep the structure balanced and durable without making it heavier than it needs to be.
- Panel Length: Spacing between panel joints typically ranges from five to ten feet. Keeping this distance consistent is key to making sure the load spreads evenly across the whole truss.
Keep in Mind: Truss dimensions are never one-size-fits-all. They must reflect your specific load requirements, roofing materials, and environmental conditions. Consider always referring to local building codes and consult a licensed structural engineer to ensure your design meets safety and compliance standards.
Single vs Double Howe Truss: What’s the Difference?
Not sure whether a Single or Double Howe truss design is right for your project?
The answer depends on how far you need to span, how much load you expect, and how complex your build can be.
While both options share a similar structural foundation, the Double Howe truss is built to do more, especially when larger spaces and heavier loads are involved.
The table below highlights the key differences to help you compare at a glance.
| Feature | Single Howe Truss | Double Howe Truss |
| Span Range | Up to 30 ft | 30–70+ ft |
| Structural Complexity | Moderate | Higher |
| Number of Diagonals | 1 per panel (each side) | 2 per panel (each side) |
| Material Usage | Less | More |
| Load Distribution | Good | Excellent |
| Common Use | Residential | Warehouses, barns, factories |
Double Howe Truss Use Cases and Design Details
Where does the Double Howe truss perform best?
If you need to cover a large area without interior supports and want consistent structural strength across the entire span, this truss system delivers. It is built to handle demanding conditions and heavy roof loads with ease.
Let’s look at where this truss is most commonly used and why its design works so well in those settings.
Common Use Cases
Agricultural Structures: Ideal for barns, grain storage buildings, and machinery sheds where wide, open interior space is essential.
Commercial Warehouses: Used in warehouse roofs to maintain structural integrity across long spans without interior columns.
Industrial Roofs: Performs well in large-span roofs for factories, workshops, and assembly plants that require durable, low-maintenance framing.
Key Design Details
- Built with multiple panels and symmetrical tension members that mirror each other from both ends toward the center.
- Engineered to provide extra reinforcement at the center of the truss where load stress is highest.
- Designed to support heavy roofing systems or environmental loads like snow and wind without sagging or shifting.
Final Thoughts
Double Howe trusses may look complex at first glance, but their logic is simple: double the diagonal supports = double the internal strength. They are an excellent solution for projects where structural failure is not an option.
Whether you’re building a farm warehouse or a commercial roof, understanding this truss system will help you make informed, safe design choices.
If you’re planning a wide-span project and need expert guidance on custom truss design, the team at Structural Wood Corporation is here to help. We specialize in delivering engineered wood solutions built for strength, precision, and performance.
FAQs
What is a Double Howe truss?
A Double Howe truss is a roof support system with two sets of diagonal members designed for wider spans and heavier loads.
Is a Double Howe truss stronger than a regular Howe truss?
Yes. It provides better midspan support and load balance over longer distances.
Can I use a Double Howe truss in residential construction?
Yes, but it’s more common in large-scale or commercial structures due to its complexity and size.
How do I calculate the forces in a Double Howe truss?
Use structural analysis methods like the method of joints or FEA software such as STAAD.Pro.
What are the disadvantages of using a Double Howe truss?
It uses more material, costs more, and requires precise assembly.