Roof Only Pole Buildings – Again
Roof only pole buildings are most often appealing for one reason, consumers believe they are going to take fewer materials – after all there are no walls! Therefore, be less expensive!
An interesting article, written by Eric Beavers (COO of Armstrong Steel Buildings) appeared recently in Rural Builder Magazine, detailing the challenges of engineered design for roof only all steel buildings. The full article can be read here: https://www.constructionmagnet.com/rural-builder/the-peculiar-thing-about-a-roof-only-steel-building
I appreciated Beavers’ comment, “Finally, here’s the big take-away from all this. Some steel building sales people and even some contractors are going to tell your customers that a roof-only structure is going to cost him less than a sheeted building. This should be a huge red flag for your customer. It means they don’t understand the basics of engineering. I get it—as I said, not a lot of people do, but that doesn’t make it ideal, or even OK.”
My long-time readers will recognize the name Frank Woeste (no, not the German born Frank Woeste of Frank Woeste Trio jazz music fame). If you are a LinkedIn member, you can read Frank’s bio at: https://www.linkedin.com/pub/frank-woeste-ph-d-p-e/24/b20/194
For the few of you who didn’t read Frank’s bio, I will summarize it by saying I should hope to someday know as much about post frame buildings and their design, than he has forgotten!
When it came to be questioned about roof only pole buildings, Frank’s advice was to just not do them – period.
I’ve railed about roof only buildings in the past: https://www.hansenpolebuildings.com/blog/2014/04/hay-barn/
There are some cases where a roof only structure is the best design solution. For these building owners, they pay a premium (as compared to an enclosed or partially walled structure) for their roof only building in the form of one or more (or all) of the following:
Larger diameter holes
Deeper holes
More concrete backfill in holes
Larger dimension columns
Increases in prefabricated roof truss member sizes/grades/steel truss connector sizes
More truss bracing
Increased fasteners requirements, especially in truss to column connections
Purlins – closer spaced/larger dimension
Considering investing in a roof only pole building? If so, consider if gaining some “free walls” might not be a bad idea
I want a rough cost estimate on a roof only building to cover a 14′ x 55′ mobile home in Show Low, AZ
Thank you for your interest in a new Hansen Pole Building. A Building Designer will be reaching out to you shortly.
Looking for prices on a roof only structure to cover a 16 by 66 single wide home in north Idaho.
Thank you for your interest in a new Hansen Pole Building. A Building Designer will be reaching out to you shortly.
Ok I was going to stay out of this because my knowledge of steel structures is limited . However , I was a truss designer for 10 plus years and unless there is some odd properties in steel as compared to wood . Because a wood truss on a pole barn or such open building type is the most inexpensive truss you can get. Requiring the least amount of bracing and often truss spacing of $6” to 48” oc . And that crazy comment about get some walls . That is the worst thing you can do some walls meaning a partially enclosed space is the highest uplifts you will ever see . With a fully enclosed space behind that . The roof you see in a tornado is from a house with walls where the roof was designed for an enclosed structure and a window or windows broke and now the wind is inside the house where it wasn’t designed to be so there transference pressure build up from air not being able to escape fast enough lifts the roof off. You don’t have that problem with an open structure . The wind flows freely through the structure with little to no uplifts. Baring some drastic change in wind speed analysis I can’t see why anyone would think differently. I would often see uplifts less then 1000 lbs for the entire job. Now there maybe factors for steel not associated with would in which case I’d say go with wood then your truss company should give you one hella good price pole barns are dream jobs there great for production numbers they only have to set the jig once no matter how many trusses you want . The saws and the cuts all set once . They can usually fit you in between jobs so your turn around time is nothing . I’m not trying to sell you on wood I’m looking for a steel building myself not wanting wood do to upkeep
The problem comes from the columns. In a roof only building, there is no way to transfer wind shear loads from roof thru endwalls to ground, therefore the columns are doing all of the work. This increases the applied loads to the columns by a factor of 4.