If your roof has trusses — and it most likely does — it relies on gusset plates to stand strong. These small metal connectors are what hold your roof’s framing elements together. But what happens when they fail? You could be dealing with sagging beams, leaks, or worse.
In this post, we’ll break down what gusset plates do in roofing and framing systems, where they’re used, and how to avoid the common failures we see in the field.
What Are Gusset Plates?
Think of a gusset plate as a connector. It’s a flat piece of metal or wood that links parts of a structure at the joints, like where beams, rafters, or trusses meet. When installed correctly, it keeps everything tight and aligned under pressure.
You’ll often see gusset plates connecting roof trusses, holding together the angled wood pieces inside your attic or garage. They’re also common in decks, sheds, and bridges.
Gusset plates come in different shapes depending on the job. Triangular, rectangular, trapezoidal, circular, and oval designs all help distribute force based on how the structure is built. You also have the option to choose from wooden gussets and galvanized steel options.
Why Gusset Plates Are Important In Structural Engineering
So, what is the purpose of a gusset plate? These small pieces play a big role in keeping your structure sound.
At A. Fricker Roofing and Waterproofing, we’ve seen cracked trusses held together by undersized gusset plates that homeowners are unaware of until their roof starts sagging. That kind of hidden weakness can become a real safety issue during storms or under heavy snow loads.
Here’s what gussets are meant to do:
- Transfers loads across structural joints: Instead of letting force concentrate at a single joint, gusset plates distribute it across a wider area. This reduces the chance of sudden failure under heavy weight.
- Distributes stress more evenly: Beams, trusses, and rafters stay aligned and locked in place, especially during storms, high winds, or heavy snow.
- Essential in bracing connections: Roof trusses, wall frames, and steel structures all rely on gusset plates to stay rigid and secure under pressure.
Note: Don’t confuse gusset plates with stiffener plates. Stiffeners reinforce parts, but gussets actually connect them. One supports, while the other holds everything together.
How Do Gusset Plates Work In Homes?
When pressure hits your roof (from wind, snow, or settling), it travels through beams and joints. Gusset plates absorb and redirect that force to keep everything aligned.
In Oklahoma’s high-wind zones, we’ve seen trusses fail when just one gusset plate was poorly installed. That’s why correct placement and durability matter — not just code compliance.
- Compression: When parts of the structure are pushed together, the plate helps prevent buckling or collapse at the joint.
- Tension: When elements are pulling apart the gusset plate holds them securely so they don’t separate.
- Bending: Some joints experience flexing forces. A well-designed gusset plate helps resist that movement and keeps the angle stable.
For a gusset plate to work the way it should, three things need to line up:
- Alignment: The plate won’t distribute force evenly if the pieces connected aren’t positioned correctly.
- Material strength: A plate that is too thin or weak can fail under pressure.
- Connection quality: Whether it’s bolted, welded, or part of an HSS gusset plate connection. How it’s attached matters just as much as the material.
Quick note: Gusset plate buckling can happen when a plate is too small or poorly installed. Engineers run precise calculations to size them for each load and lay them out correctly. This is why it’s so important to have an experienced professional install your roofing system.
What Materials are Used in the Gusset Plates
Not all gusset plates are created equal. The material you choose affects durability, performance, and suitability for your specific project. Here are the most common types:
#1 Steel
Steel is the go-to for most roofing and structural gusset plates. It’s strong, durable, and easy to weld or bolt. Galvanized steel offers rust protection for outdoor applications, while cold-rolled steel provides a smoother finish, often used in high-performance framing. Steel is ideal for homes, garages, decks, and any exposed truss or framing system.
#2 Wood or Plywood
These gussets are common in residential roof trusses and small DIY builds. They’re easy to cut and install, but they don’t hold up as well in outdoor or high-stress areas. For exterior use, choose exterior-grade plywood and seal it against moisture.
What Are The Types and Classifications of Gusset Plates?
Gusset plates can be grouped by where they go and what shape they take. Each type plays a specific role in how force is handled across a structure.
By Function and Position
- Column gusset plates: Found where vertical columns meet other structural members. These help secure upright load-bearing points.
- Corner gusset plates: Used at angled joints, especially in wood and steel framing. They help lock corners in place.
- Intermediate gusset plates: Placed between long spans to support force transfer across beams or trusses.
- Beam gusset plates: Added at beam intersections to strengthen the connection and reduce joint stress.
- Angle gusset plates: Used in L-shaped framing or angled joints where reinforcement is needed for added stability.
By Shape
- Triangular and trapezoidal: Common in gambrel roofs or for wood trusses where angled framing is used.
- Rectangular and square: These are Typically used on flat joints, such as decks, garage framing, or basic wall bracing.
- Circular and oval: Found in custom or performance-heavy designs like aircraft structures.
- Bridge gusset plates: Vary widely in shape and size depending on the truss design. These are engineered for extreme loads and long-term wear.
What Connection Methods Do Gussets Use?
There are three main ways to attach gusset plates:
- Welding: Strong and permanent. Best for steel framing and high-load applications. Requires professional tools and training.
- Bolting: Most common in residential and light commercial projects. Works well with wood or metal and allows for future adjustments.
- Riveting: Seen in older buildings and restoration work, this method is reliable but rarely used today due to more accessible alternatives.
DIY Installation & Practical Tips
If you’re working on a shed, truss, or light framing project, installing gusset plates is something you can handle with a few tools and a bit of planning. Here’s what to keep in mind:
Making Gusset Plates
For outdoor framing, galvanized metal is the better choice. Untreated wood gussets won’t hold up in Oklahoma’s heat, moisture, or storms and will likely rot or shift within a few seasons.
Designing the Right Fit
If you’re building a shed or repairing a roof truss, don’t overcomplicate it. Your gusset plate should fully cover the joint and overlap each connected piece by a few inches. Use fasteners spaced evenly across the plate to avoid weak spots.
Dimensions and Thickness
Use ½-inch plywood or 18-gauge steel for most residential builds. For longer spans, increase the thickness as needed.
Tools and Materials
Most homeowners can install gusset plates with just a saw, drill, and bolts. You don’t need welding gear, just solid tools, quality materials, and a little planning.
Common Mistakes
What are the biggest mistakes we see? Gusset plates that are too small, poorly aligned, or attached with fasteners too close to the edges. Another common issue is using thin plywood or raw steel in outdoor builds. In Oklahoma, where high winds and sudden weather changes are common, we’ve seen improperly sized gusset plates lead to real structural issues.
Safety, Fire Resistance, and Maintenance
Gusset plates don’t just hold things together. They also have to withstand stress, especially in harsh environments like high heat, moisture, or general outdoor exposure. Knowing how to protect and maintain them can make all the difference in your structure’s long-term safety.
Fire Performance
In high temperatures, metal gusset plates can lose strength once they pass 500°F. Wood and plywood versions are even more vulnerable if they’re not treated. If you’re building in an area where fire safety is a concern, choose materials accordingly and consider fire-rated coatings.
Inspections and Maintenance
Over time, gusset plates can rust, shift, or degrade. Look for surface corrosion on metal plates, rotting wood gussets, or any signs of loose fasteners. Small issues can lead to major failures if left unchecked, especially in outdoor or high-moisture areas.
Protection Tips
Use galvanized or coated steel in exposed conditions. For wood gussets, apply sealant and stick to exterior-grade materials. Protective coatings don’t just extend the lifespan of the roof, they help prevent failure when it matters most.
Repairs and Reinforcement
If a gusset plate is damaged, don’t ignore it. Replace it or add a second plate to reinforce the connection. Reattach fasteners if needed, and always make sure the joint is tight and aligned. If you’re unsure how to fix it, a local contractor can help you get it right.
Lifespan
When installed with the right materials and maintained properly, gusset plates can last for decades. However, like any other structural component, they need regular attention to stay reliable.
What Are Decorative & Architectural Gusset Plates?
Gusset plates aren’t always hidden. In some homes and custom builds, they’re used as visible design features, especially around exposed beams and trusses. A well-placed gusset plate can add a clean, industrial edge or a rustic, hand-built feel.
Galvanized gusset plates are a popular choice for this kind of look. They resist rust and keep their finish over time. That makes them ideal for outdoor framing, vaulted ceilings, or open-concept entryways where structure and style work together.
Need Help Choosing the Right Gusset Plate?
We’ve covered why gusset plates matter, how they work, and what to look for when installing or maintaining them. If you’re unsure which type fits your project or want to make sure it’s installed correctly, we’re here to help.At A. Fricker Roofing and Waterproofing, our experts are ready to handle whatever roofing project Oklahoma homeowners need. Call us at (918) 402-7167 to learn how we can help you, or check out our blog posts for more roofing tips and expert support.
