Tag Archives: structural engineer

Cutting Barn Trusses

Just a Little Nip Here, Tuck There

As so many of us have entered an age of Covid-19 binge television watching, I can imagine there are more than a few who have consumed calories while watching 100 episodes of Nip/Tuck (originally aired on FX from 2003-2010).

While nipping and tucking can solve many human cosmetic issues, it is done by highly skilled professional surgeons. Want to nip and tuck on a building’s structure? You wouldn’t hire a bus driver to perform plastic surgery, so don’t try to be your own structural engineer.

Reader BRIAN in ANDERSON writes:

“I have a barn, 40 foot wide, 36 feet long.  I need to increase the height of the front garage door to fit an RV, and need to modify a single truss in the front of the building to make room for a roll-up garage door (barrel door).  The trusses are engineered attic trusses, and span the 40′ without any support.  The distance between the web members that would make up the “wall” of the attic room, is just over 16′.  The door is 16′ wide.  So I need to get some more room between the web supports, and remove a section of the bottom chord.  I will be raising the middle section of the bottom chord by 26″. My plan is to modify the truss in two ways:  First create a new bottom truss to effectively turn this single truss into a coffer truss, and widen the web members.  The new bottom chord will sandwich the existing truss elements with a new 2×10 on each side, and gaps of the new chord path filled in effectively making a solid beam 3 boards wide (considering construction adhesive between the layers as overkill).  Including some drawing showing the steps I plan to take.  Probably overkill, maybe not enough, just want a reality check on the plan.  Also, trusses are 24″ on center.”

Mike the Pole Barn Guru responds:


Never, ever cut a truss without having an engineered repair. Ideally this could be obtained from whomever manufactured your building’s trusses originally. If you are unsure, there should be a manufacturer’s permanent ink stamp on each truss bottom chord. Should you not know who fabricated them, stamps are not able to be found or manufacturer is no longer in business, hire a local Registered Professional Engineer to come examine your trusses and provide a repair drawing (if it is even possible to be done).

For extended reading on not cutting trusses: https://www.hansenpolebuildings.com/2016/07/cutting-trusses/

Proposed Building Code Change to Add to Construction Costs

During each 3-year-cycle of the International Building Code (IBC) and International Residential Code (IRC), there exists an opportunity to propose modifications and improve the codes to recognize new and innovative construction.  During the final two weeks in April, the code proposal hearings were held in Louisville, Kentucky where several hundred proposals were discussed and considered for inclusion in the code.

large-span-trusses-150x150While post-frame construction is typically used in agricultural applications which are often (and in my humble opinion sadly) considered exempt from code compliance, more and more post-frame construction is either residential housing (IRC) or commercial (IBC) in nature.  In these cases, changes which impact the code may have an effect on how post-frame buildings are constructed.

Eight proposals were identified by NFBA (National Frame Building Association) staff as having a potential impact on post-frame construction.  While the majority of these proposals were defeated, the following action should be noted:

S138-16: Submitted by the Structural Engineers Association, this proposal was approved and will require special inspection for wood trusses with a clear span of 60 feet or greater or an overall height of 60 inches or greater.  While the clear span is not a major issue, the 60 inch height may impact a number of projects creating new cost/scheduling issues.  This change is scheduled to be included in the 2018 IBC.

Having spent my entire adult life installing, designing, selling, building, delivering and purchasing wood trusses, it would seem ludicrous to require a special inspection for wood trusses with an overall height of 60 inches or greater. This would add an extra layer of inspection to nearly every building (not only post frame) project, with seemingly no apparent rationale other than the employment of a large number of people to perform these inspections (most likely the same structural engineers who made this proposal).

Trusses spanning 60 feet or more, are already required to have special inspections, under the IBC: https://www.hansenpolebuildings.com/2013/12/wide-span-trusses/.

What can you do? Contact your local Building Official today and ask them to vote to repeal this costly measure which does little or nothing to improve the safety of buildings.

My Early Urban Garage Experiences

In the 1980’s one man stood alone when it came to whether City of Portland (basically the same thing as Multnomah County), Oregon homeowners could acquire a Building Permit for a residential accessory building or not.

Charles “Chuck” Frazier

Now Chuck was a registered Structuurban pole barnral Engineer, who took his position very seriously. His expectation was, if a structural permit was going to be approved by him – then the permit applicant, better have his (or her) structural ducks lined up in a perfect row!

So fearsome was his reputation, many builders (especially those who constructed pole buildings), would put right on their newspaper ads, “We do not build in Multnomah County”.

While I never had the opportunity to meet Chuck personally, when I had my first pole building kit package business in Oregon, I had the opportunity to deal with him by phone on many what I will call “urban garages”. I was young, and pretty naïve, so early on I just asked him specifically what it was he wanted, in order to issue a permit for a pole building garage.

In a nutshell, he wanted the calculations to verify the embedment of the columns (how deep and what diameter) and for the size, grade, spacing of columns, sidewall girts and roof purlins. Not being an engineer – I asked him for an example, which he provided.

Using his example, we provided hundreds upon hundreds of pole building urban garages across Metro Portland. Portland was laid out with numerous postage stamp sized lots, many only 25 to 35 feet in width. These are especially prevalent in the Northeast area, where many single family homes were built on them after World War One and before the Great Depression. By the 80’s people found they could purchase these 60-70 year old homes for next to nothing and many neighborhoods began to revitalize themselves. One fairly consistent lacking feature of these homes – most of them did not have garages!

Pole buildings were a perfect fit for these homeowners. Many of them were relatively young, and willing to put sweat equity into the fixing up of their (new to them) older homes. Pole buildings are able to be of any dimension, and therefore allowed for the maximization of building footprint to available space. With the only foundation being holes augured into the ground, it was pretty “low tech” compared to the invasiveness of having to excavate for footings and foundations, as would have happened with what many would consider to be more traditional “stick framed”.

And, because construction goes so quick, many urban garages started Friday after work, and were completed over a single weekend!



Engineer – It Ain’t Amtrack

I once heard an anecdotal story about a man who had a choice to stand in one of two lines – for brains, or trains. He had always wanted to be an engineer, so he picked the line for trains….

OK, so it wasn’t necessarily funny.

If you’ve ever been involved with a commercial building, it was probably designed by a Registered Design Professional (an RDP – an architect or engineer). Ordered prefabricated wood roof trusses? Again, they were probably manufactured from designs created by a registered professional engineer (P.E.) or a structural engineer (S.E.).

In reality, virtually any structure was either designed by an RDP, or should have been.

Most architects subcontract the structural portion of their designs to an engineer. Engineers specialize in their ability to “run the numbers” to prove on paper why things will or will not perform in the real world.

An engineer is responsible for the analysis and design of the structure or framing system of a building or building component. While doing the building’s structural design, the engineer will take safety and performance into consideration.  For performance or serviceability this is the design for vibrations from machinery, floor vibration or deflection which could cause discomfort, or even building deflection or sway.  The occupants of a building might feel uncomfortable if the building sways or moves too much, especially on the upper stories.

An engineer’s qualifications can be verified.  The easiest thing to do is to check if the engineer has either a Professional Engineer (PE) license in civil engineering or their Structural Engineer (SE) license in the state which the project is being built.  Some states don’t offer a SE license so this is why there is a difference in the title.  While there is a nationally recognized test for engineers, there is no general licensing, it is state specific and each state has their own requirements to obtain and maintain registration.

Okay, so this is a general definition of the responsibilities of an engineer, how does it pertain to post frame buildings?  Pole buildings, for engineers, involve the same responsibilities and analysis as any other structure, but it all pertains to one specific material.  Very few RDPs are familiar with post frame construction and design pole buildings on a regular basis. If hiring an engineer to design a pole barn, look for one with extensive experience – hundreds of post frame buildings designed, not just five or ten.

Be wary of anyone (builder or company) who says “I’ve done pole buildings for 10 years,” but has no engineering background nor degree.  Does this mean he can verify the design he uses will be safe? Is it economical in design or did he just put a lot of lumber into it, many dollars of it which does nothing for the building and a lot for depleting your funds?  Does it have verifiable calculations to prove it will stand the test of time and nature?  Or does it mean buildings have been built over ten years and fortunately none of them have fallen down – yet?  Companies which supply complete pole building kit packages have ongoing relationships or employ engineers who have the expertise it takes to design safe and economical structures, which will perform admirably for generations.  Don’t be caught “un-insured”.  Make sure your building has an engineer’s stamp of approval on your building plans.