The truth about trusses: purchasing, safe handling and installation

Two businesses that take truss safety seriously are the makers of truss systems, Plum Building Systems, Iowa, and Blenker Building Systems, Wisconsin.

Plum Building Systems

Plum Building Systems photo

Rick Parrino, generation manager of Plum Building Systems, a division of Gilcrest/Jewett Lumber says their company makes sure every jobsite delivery includes a packet of BSCI standards. Because all the layouts and drawings are included in the packet, with a large orange warning sheet in the cover asking them to ‘Read the Safety Documents’, the builder is forced to take a look. “We stick all their information in [a big zip-lock bag] so they have to open it up (we hope they read it), just to get their layouts and truss drawings out,” Parrino says. It’s a way to educate framers and to warn them not to become too complacent about their work.

Education isn’t just for framers, though. “We’re always looking for ways to educate ourselves and to be better at what we do, Parrino explains. “We don’t want to be doing something that will do damage to our industry or to our reputation as a company and a truss builder.”

The packets of information provided include specific information for builders of agricultural buildings. “It’s very dangerous setting trusses, especially very large agricultural trusses and church trusses,” Parrino says. “They are the most common ones that come down.”

There are various reasons for that. For ag buildings, it can be due to the number and span of trusses. “The thing about ag trusses is that they’re farther apart,” Parrino says. “Most people build them 4 foot on center, 6 foot, 8 foot on center, in fact sometimes 9 foot on center. The average house span is 30 to 32 feet. The average ag span is 50 or 60 feet, so it’s twice as long. Because they’re so far apart it’s so hard to get out there and brace them together.”

The last couple of winters have brought heavy snowfalls to the Midwest and also more ag roof collapses. Parrino believes he knows why. “People often want to save money and they ask the truss suppliers to build their projects with the minimum amount of loading possible. Many times they will ask for no ceiling load because it’s just going to be a storage shed.” These requests, he explains, can lead to trouble down the road. “They say it’s just going to be a storage shed, but then later they turn it into a shop and add a ceiling and lights, or they will add feed equipment for animals. The trusses were not designed for that load.” Add a heavy snowfall, and disaster strikes.

Another common issue for ag buildings is inadequate side wall bracing. “Side walls on ag buildings are sometimes 16-, 18- or 20-feet tall. But because they don’t make a lot of longer lumber any more, what guys will do, they will brace only up as far as they can get lumber to reach, 10 maybe 12 feet,” he says. This weakens the wall’s bracing effectiveness at the top. “The very top can still move around on them.”

Professional builders may know the pros and cons of good truss installation, but ag buildings, as well as church buildings, are not always built by experienced builders. Ag buildings are sometimes built by farmers. “Sometimes they’re using a tractor with a bucket to lift the trusses into place,” Parrino says. “They don’t have the proper lifting equipment. They’ll use a chain to pick it up right from the center. There’s two things wrong with that: one, they damaged the connector plate in the center of it; and two, the truss is not designed to be picked up that way. You put a huge stress load on the middle of that truss which can start to pull that connector plate or the joints apart.”

On the other hand, church buildings are sometimes built by volunteers. “Maybe it’s a guy who builds houses or garages for a living, and comes and volunteers to put it up, but they’ve never handled anything that large before,” Parrino says. “They’re not using the proper equipment, not using a spreader bar to lift and hold [the trusses]. Long span trusses tend to fold in half because of the excessive weight on the outside, creating a hinge affect in the center, even in a slight wind, so there’s a lot more danger in that.”

Jason Blenker, whose family has a long history in general contracting (Blenker Construction) as well as component manufacturing (Blenker Building Systems) is concerned about some experienced contractors who don’t take common safety precautions, such as adequate fall protection. “I see a lot of guys climbing around in trusses, basically working unprotected greater than 6 feet off the ground,” he says, adding, “probably more so in ag buildings, because they tend to be in more rural areas and they’re not so much under the watchful eye of OSHA.”

With today’s ag buildings often larger than in the past, and farmers doing fewer DIY projects, there’s little excuse that proper loading and installation requirements are not followed by today’s builders who have better access to information than ever before, but Blenker says he sees attempts at bypassing safety for the sake of cost.

“Ag allows an exception – or a reduced load on agricultural type buildings – which makes them inherently, I don’t want to say more susceptible to failure, but there’s more allowed, because there is no human-life danger,” Blenker explains. “So sometimes I see people getting ag trusses and using them on projects that aren’t low-hazard buildings. They’re using them for shops and milking parlors, whereas the intention of the exemption is for storage buildings only. They’re trying to get under those exemptions, where in reality those should be commercial-type load trusses.”

Proper selection and proper handling are a must. “When you get into ag buildings you get into some long span trusses,” he continues to emphasize, adding, “and you need to have the proper hoisting equipment so you’re not bending the trusses in ways they aren’t designed.”

When in doubt both Blenker and Parrino advocate: always check your Installation Guidelines Packets for your BCSI and follow the SBCA’s “Guide to Good Practices for Handling, Installing, Restraining & Bracing Metal Plate Connected Wood Trusses.” – By Sharon Thatcher, Rural Builder

Related article:
What you should know about roof truss connectors in load capacity



Rural Builder October 2011 FREE subscription to Rural Builder magazine…
FREE subscription to Frame Building News…
FREE subscription to Metal Roofing Magazine

Related Posts:

  • No Related Posts