Structural Engineering

I’ll take Structural Engineering for $XXX Alex

Proper Engineering in post frame construction can not be overlooked.

Alex Trebek has hosted Jeopardy!, the iconic daily syndicated game show, since 1984. With over 7,000 episodes aired, Jeopardy! has won a record 33 Daytime Emmy Awards. Some of you may even have tuned in for an episode or three.

Today’s Answer Is:

Insufficient Data to Provide an Answer

And reader PAUL from FINKSBURG has the question:

“What size header would be required for a 20′ wide overhead garage door placed on the truss bearing wall?”

Okay, enough of my being snarky. The answer to Paul’s question should be clearly indicated on the engineer sealed plans for his building, along with the required connections from truss to header and header to columns.

If somehow the engineer of record overlooked this critical element, he or she should be contacted immediately to provide the missing data. Even worse – maybe an engineer happened to not design the building, in which case CALL ONE NOW.

Whilst this may appear, on the surface to be a simple question, there are a plethora of factors which go into the determination of a structural header to carry roof loads. This would include, but are not limited to:

Pg – the Ground Snow Load

Ce – the Snow Exposure Factor (sites which are open to the wind allow snow to blow off the roof, sites which are protected from the wind keep snow on the roof)

Is – the Snow Load Importance Factor (Risk Category I buildings are a lower hazard to human life, therefore the flat-roof snow load will be reduced)

Ct – the Thermal Factor (heated buildings melt snow off, unheated buildings allow snow to build up)

Pg, Ce, Is and Ct are multiplied together along with 0.7 to determine the Flat-Roof Snow Load (Pf)

But wait, there is more…..

Pf might be further reduced depending upon the roofing material (steel roofing being slick allows snow to slide off quicker), whether or not snow retention systems are present (which hold snow on the roof), as well as the roof slope. Mix them all together and the Sloped Roof Snow Load (Ps) is created.

The dead loads imposed upon the roof also need to be added to the mix – the weights of trusses or rafters, purlins, roof sheathing, insulation supported by the roof system, roofing, truss bracing, ceilings are amongst some of the weighty culprits.

Once all of these contributing factors are combined into a psf (pounds-per-square foot) load, concentrated loads are applied to each of the truss bearing locations along the header – these are based upon ½ of the truss span (including any sidewall overhangs) multiplied by the truss spacing and the applied loads.

Not only does the header need to be verified for adequacy in load carrying capacity, but also limited in deflection. A sagging header can cause unsightly rooflines as well as preventing doors from operating correctly.

Self-engineering is not a good choice – call your engineer….now!

6 thoughts on “Structural Engineering

  1. Shawn P Garland

    Good Morning. I would like to speak to someone regarding structural engineering for a pole building.

  2. Hello I have a floor plan for a residential building but would like it engineered and drawn up as a pole building. Was wondering about time frame and if you have the ability to draw it up to pass the grant county wa aspects to get the building permit.

    1. Yes, we can convert your floor plan into a third-party engineer sealed post frame (pole) building with the ability for you to acquire a structural permit. One of our Building Designers will be reaching out to you shortly or dial 1(866)200-9657 to speak with one now.

  3. Hi, I’m designing a 50′ x 200′ pole barn. I want to use 4 1/2 inch drill pipe for posts on 12 foot centers and 2 3/8 drill pipe for horizontals on 4 foot centers with a 6×4 twelve pound I beam header all along the long sides. The walls will be 12′ high and skinned with painted 36 inch metal siding/roofing panels. The roof will be 4/12 to 6/12 pitch wood attic trusses (the truss manufacturer will provide engineering) on 24 inch centers with 2×4 perlins laid flat on 4 foot ceters(or closer if needed) with the 36 inch roofing panels attached to the cross perlins. I will draw the plans. Could you do a plan check and provide engineerimg for my walls and posts and certify the plans for Salt Lake County,Utah. The snow load for my lot is 50 psf and the ground snow load is 70. My address is 14725 so. Majestic oaks ln, Herriman Ut 84096. Would this be in your $400 range?

    1. You might want to read the article.

      Hansen Pole Buildings provides complete, custom designed third-party engineered post frame building kit packages. We do not provide or design buildings using pipe, or trusses place upon I beam headers. Your idea of attic trusses is also probably flawed – most truss manufacturers are limited in their ability to produce and ship trusses over 12′ tall in one piece. A 50′ truss at 6/12 slope without any overhangs is going to be 13′ or more in overall height and your usable “bonus room” will be relatively small. At 4/12 slope any bonus room will probably include ringing your head.

      Engineering law prohibits you from drawing your own plans and having an engineer seal them, plans must be produced under supervision of the engineer.


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