Best Practices, Feature, Operations, V5I2

Building a Better Roof Truss

Metal plate connectors are meant to be hydraulically pressed into roof truss joints. (Photo courtesy of the Truss Plate Institute)

A roof truss, simply put, is a wooden frame that supports the roof of a built structure, like a shed.

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There are many ways to design and connect trusses, and shed builders often have their own techniques and styles.

“A lot of it is, ‘This is how I’ve always done it,’ or, ‘This how my dad taught me to do it.’ It’s not really an engineered design, but it works,” says Jay Jones, technical director at the Truss Plate Institute (TPI).

While a truss process may work, there are ways a builder can improve roof truss construction in terms of effectiveness, cost, and supply.


Before looking at roof truss construction, shed builders need to consider whether or not their structures will be subject to building codes, which would mean the roof trusses would have to be approved. 

“If you’re in a location and the building is of a size that it has to be built per the code, that would automatically kick them into having to build their trusses per ANSI/TPI 1, which is the design and construction standard for metal plate wood trusses,” says Jim Vogt, director of technical services for the Structural Building Components Association (SBCA)

“I would think they would have a hard time getting that approved by a code official without getting an engineer’s seal on the truss. Typically, that’s how it’s done.”

This is especially important if a builder is constructing his own trusses. 

“When they start to get bigger and need a building permit, most likely the building inspector is going to want to see an engineered drawing for those trusses,” adds Jones.

Builders can improve roof truss construction in terms of effectiveness, cost, and supply.

And whether or not a structure needs a building permit, both Jones and Vogt see roof trusses being constructed two ways: either with a metal connector plate or wood gussets (OSB or plywood). 


Mark Lambright, owner of Golden Rule Machine, which supplies truss presses to shed builders across the county, says that roof truss construction by builders can result in more productivity, more bottom line.

“I encourage builders to evaluate the time and effort involved in truss construction,” he says.

If a builder is using metal connector plates, with “teeth,” those are supposed to be hydraulically pressed in, Jones says. 

“You could put the connector plates on, beat it on, it would hold together, but as far as the published values, they’re only good for those values if they’re hydraulically pressed,” he points out. 

Vogt says that metal connector plates are typically 20-gauge steel plates that have been punched in a certain pattern to form a tooth of about 3/8th inch in length. 

He adds that connector plate manufacturers have done a lot of research in how the pattern is laid out to maximize the strength of the plate connection using various species of wood. 

“Some of the orientations for the way the plates can end up on a joint, depending on the pattern that’s used, you can have as much as a 20 percent difference in certain orientation between plate A versus plate B,” says Vogt. “While the numbers are close, there can be differences.”

Most often when it comes to metal connector plates, the industry manufacturers have proprietary software to design the trusses.

“For a shed manufacturer to want to try to build their own trusses using these types of connector plates, I would think they would have to have some type of relationship with one of these plate manufacturers to be able to use their software,” Vogt says. “The software is pretty versatile. Literally anything you can dream up can probably be designed.” 

There are metal connector plates with nail holes in them that a builder could purchase through a supply store. The builder simply puts the plate on a joint and nails it on. 

“The problem with something like that is a lot of times those connector plates, if the structure needs to follow code, a code official would say I need proof that what you have built will work because there are not any prescriptive requirements in the building code for that,” Vogt points out. “You can’t go to the table.”


Trusses that use dimension wood, 2 by 4 or 2 by 6, can also be constructed in a shop using OSB or plywood cut in triangular shapes, called gussets, nailed onto the joint. 

“It’s pretty labor intensive,” says Vogt. 

Jones points out that many roof “frames” for sheds have to interact with the diaphragm of the roof, the walls, and the end walls to hold it all together, because the frames want to push out. The plywood holds it all together. 

“Somebody building these on their own, I know it’s done, and it’s just best practice using plywood gussets and staples, as many staples as you can get into that gusset,” he says.

Vogt says that when a builder uses a nailed-on gusset, they are limited by the nail value and the thickness of the gusset. 

“With nails, one of the things I would ask is are they using the formed shank nail,” he says. “Whether it’s a ring shank or a screw shank or barbed or something like that, that’s typically going to have better withdrawal values.” 

Nail length is also a factor. For example, using a 7/16th gusset and 2 by 4 connected with a 3-inch nail, some of the nail will stick out the other side. This can be clinched, creating a double shear value. 

“If they’re using just a 2.5-inch nail, say they’re driving it through half-inch OSB/plywood, 1.5-inch member, that nail is not sticking out the other end,” Vogt points out. “That’s fine, but you have to use a single-shear nail value, so you have to drive the one nail on the one side and then you have to come on the other side and drive another nail in to have the joint loaded symmetrically.”

The thickness of the material used for the gusset also affects the span rating, that is, how far apart the trusses can be spaced along the roof. 

When it comes to using OSB or plywood for gussets, Vogt says that OSB is more commonly used.

“One, it’s more common than plywood,” he points out. “Number two, because it’s a pressed material, you typically get a higher specific gravity than you do with plywood. That’s one of the factors that determines what your allowable lateral resistance of your nails are. The higher the specific gravity, the higher the nail value.”


While many builders opt to construct their own roof trusses, another option is to have them supplied by a truss manufacturer. 

Going this route, a shed builder would have the knowledge that the trusses are designed and engineered by experts, and they can order inventory at any time.

“If you go to a truss manufacturer, you could say I want a 4 ½ 12 pitch or a gambrel shape or whatever shape you want, and they can pretty much design it for you,” Jones says.

“It’s not unheard of for some of these truss manufacturers to have contracts with an outfit that does garages, stand-alone, for different spans and different pitches, and they’ll just crank out a whole slew of these one or two designs for that builder, who stores them and as they build, they go through their inventory and when they need more built, they let the truss manufacturer know,” shares Vogt. 

“That’s a scenario whatever they can dream up, the types of pitches and profiles and so forth probably can be designed and built, within limits, of course.”

Bottom line, shed builders need roof trusses that support the roofs of their structures. The trusses can be built or purchased, and there are ways to build a better roof truss.    

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