Tag Archives: wide span roof trusses

Wide Span Trusses

Long ago, in a Galaxy far away…..no not Star Wars, but one of my “past lives” in the 1980’s at M & W Building Supply.

It was an early Fall Monday morning – the first day at work for my then brother-in-law Jimmie Ballinger (Jimmie and I were married to sisters). Jimmie had decided he wanted to learn to sell pole buildings, so we were going to educate him. About 9 a.m., a potential customer comes into the office and Jimmie asks if he can talk with him. My response was, “You haven’t been here an hour, you have no idea what you are doing.” Jimmie tells me, “It will be alright”. Two hours later the new client leaves Jimmie in hand with a significant down payment check and a signed order for an 80’ x 204’ horse riding arena!

The client, Percy Freeman called me the next day to tell me what a nice young man Jimmie was, and asked politely if I could explain to him what in the Hxxx it was he had purchased!

Mr. Freeman, it turns out, was the inventor of the “Freeman Baler”. For those so interested, numerous videos of Freeman equipment can be viewed at: https://www.youtube.com/user/FreemanBalers

large span trussMoving forward…. Mr. Freeman’s building was all framed up, ready for steel when an exceptional wind storm ravaged it over the Thanksgiving weekend. With wind speeds reported in the area of 80 miles per hour, an unseen timber break in one of the 6×10 pressure treated columns fractured – resulting in a complete building failure.  The remains were bulldozed into a deep trench beyond the rear endwall of the building, and ceremoniously burned.

Time to rebuild….

The building was all framed up, once again, when Jim Betonte (owner of the erection company Farmland Structures) wants me to come take a look at the building. When I get there, it is quite obvious the truss on the front endwall of the building, when viewed from the side, is in the shape of a giant S – bowed out by several feet. The endwall had started out straight, but as the roof system was being framed, the S began and increased in size as more trusses were set and roof purlins put into place.  At 80’, these wide span trusses have this tendency to want to bow and flex.

We did manage to solve the S…..using the boom of one of our crane trucks, we pushed or pulled at each endwall column, starting from one corner. When the column got to straight, we would add plywood sheeting on top of the roof purlins, to create a firm anchoring point. We had originally tried diagonal and lateral bracing, but no amount of bracing would hold things in place.

When researching for yesterday’s article, I came across an SBC™ Magazine article which tells other people have experienced similar challenges: https://sbcmag.info/article/2014/long-attention-span-trusses-over-60-feet-present-bracing-challenges

There are now requirements for the owners of buildings with wide span trusses (60 feet or greater): “In all cases where a Truss clear span is 60 feet or greater, the Owner shall contract with any Registered Design Professional (RDP) for the design of the Temporary Installation Restraint/Bracing and the Permanent Individual Truss Member Restraint and Diagonal Bracing.”

In the case of Mr. Freeman’s building, everything eventually turned out just fine. And it appears things turned out fine for his business pursuits, as evidenced from this 2004 Press Release:

“Allied Systems Company purchased the assets from the 115 year-old J.A. Freeman & Son, Inc., manufacturer of modern hay baling and hay handling equipment.

Allied Systems Company, a Portland, Oregon based leader in the engineering and manufacturing of specialized heavy lift and material handling equipment has announced the purchase of the assets of J.A. Freeman & Son, Inc., manufacturer of hay baling and hay handling equipment, also based in Portland.”

Wide span trusses pose their own set of challenges, easily rectified by use of appropriate bracing for both temporary and permanent installation. Any RDP can design the proper bracing for safe building erection. Having an engineer seal your building plans is both the smart and also prudent choice.

Wide Span Trusses

The year before I started my prefabricated metal-plate connected roof truss career with Coeur d’Alene Truss in 1977, they had provided hundreds of 60 foot span trusses for a cabinet manufacturing plant. The building was being erected by an experienced contractor who had an excellent reputation for quality. For my future employer, this was their largest sale, and he proudly went out to take photos of all of the trusses, set in place.

The next morning, the trusses were on the ground, nothing but a pile of kindling! Luckily (for the truss company anyhow) the photos taken showed the truss bracing had been installed only in one direction and a puff of wind caused them to topple in the opposite direction.

As a truss manufacturer, I’ve built wide span trusses, up to 100 foot span, and as a builder installed trusses up to 92 foot.

wide span trussesHigh grade msr (machine stress rated) and mel (machine evaluated lumber) have allowed for metal-plate connected trusses to practically and affordably be designed and fabricated for spans of 100 feet and wider. The pole building industry has taken advantage of these spanning capabilities to provide wider clearspans for commercial, industrial and manufacturing industries, as well as the traditional agricultural market.

For those who design, fabricate and build with wide span trusses, code and regulation changes have occurred effective with the 2009 edition of the building codes.

For the pole building industry, the involvement of a registered design professional (RDP – engineer or architect) who can design correctly and knows what they are doing, becomes critical.

The focus on wide span trusses is due to the liability, as problems tend to grow exponentially with the size of the truss. Everything tends to become more challenging beginning with the fabrication, handling, loading and transportation from the truss manufacturer.

When I had my truss plant in Spokane, we had the opportunity to do a large project (a hockey rink) with 114 foot span trusses. We could build them, but we could not figure out how to get them around one of the corners between our location and the proposed jobsite!

With wide span trusses, installation and bracing requirements become critical. They maximize the capabilities of the installation contractor and of the components of the truss.

As the forces which must be carried by a truss (or any beam) are a product of the square of the span, what must be carried by an 80 foot span is four times what a 40 span would carry! This makes for much heavier trusses and increases the impact in the event of an accident.

The Hansen Pole Buildings Construction Guide includes information on proper truss installation. There are other sources on current codes and regulations, including Building Component Safety Information Guide to Good Practice for Handling, Installing, Restraining and Bracing of Metal Plate Connected Wood Trusses, produced by the Structural Building Components Association and the Truss Plate Institute, and Truss Technology in Buildings by the Wood Truss Council of America, Inc.

You can find it here:


My personal pole building engineering mentors, wood engineers Frank E. Woeste, PhD PE, and Donald A. Bender, PhD PE, have authored articles which urge RDPs who specify wide span wood trusses for post-frame buildings to take special note of recent changes in the 2009 International Building Code and the ANSI/TPI 1-2007 truss design standard.

Owners of a project with metal-plate-connected wood trusses spanning 60 feet and greater are now required to engage an RDP to design and inspect both temporary and permanent bracing for trusses (See International Building Code Sections 2303.4.1.3, 1704.6.2, and 1704