Tag Archives: engineer sealed building plans

I am Designing a Pole Barn

I Am Designing a Pole Barn….

These words strike fear in my heart.

Reader ELISEO in FLOWERY BRANCH writes:

“ I’m designing a Pole Barn to be 30’W x 40’L x 12’H. I’m asking for 6 trusses to be placed 8’ on center with a 4:12 pitch. I’m gonna tie them together with 2×4 on edge 24” OC. My question to you is since I’ve been reading through some books and I haven’t had a definite answer. I’ve gotten companies quote a minimum of 11 Trusses and one company actually quoted me 6 trusses like I had originally planned. Do you believe that down here in GA 8’ OC trusses will be up to Code? They will be held on 6x6x12 PT also 8’ OC.”

Elisio’s first challenge is he is attempting to structurally design his own post frame building. Maybe you have seen car commercials on tv, where a vehicle is driven at high speeds on winding roads? Ever notice a disclaimer of, “Driver is a trained professional on a closed course”? It is because you and a vehicle MIGHT be able to perform together just like on tv, however chances are fair you will possibly be injured or even die should you attempt.

This very same adage holds true with those punting at their own building design….engage a trained professional. Or even better, a complete post frame building package structurally designed by a trained professional. And when I talk about “trained professional” in this context, I mean plans sealed by a Registered Design Professional (RDP – architect or engineer) specifically for your building on your property.

Now Elisio’s asking for six trusses to be placed eight foot on center is only partially correct – it would give him a conservative design for his end trusses as they only support four feet from endwall to next truss (plus any end overhang). He might end up having spent more money than necessary. His idea of using 2×4 on edge for roof purlins may or may not work, depending upon grade and species of material. Beyond what type of 2×4 is proposed, will be its ability to withstand wind loads, as wind loads will dictate in Georgia. This, and how to properly connect purlins to trusses, is just a portion of what a RDP will be examining and verifying for adequacy.

Will trusses spaced every eight feet be up to Code in Georgia (or anywhere else)? Read here to find out: https://www.hansenpolebuildings.com/2011/06/pole-barn-truss-spacing/.

Please do not put yourself or your loved ones at risk, call 1(866)200-9657 and speak with a Hansen Pole Buildings Designer who can assist you in having a properly designed post frame (pole barn) building!

Don’t Build Without a Building Permit

ASK THE POLE BARN GURU is for everyone – those who own, or hope to own, a pole building, contractors as well as Building Officials. Here is a real life interaction with a Building Official:

“I have a customer erected pole barn 50 x 60 and very concerned with 50 foot span engineered trusses resting on 2 x 12 nailed to the sides of 4 x 6 posts at 8 foot o.c.

Please respond, my email is xxxx and I can forward some photo graphs. I am the building code official here in xxxx, and this building was erected without a design drawing.”

 Mike the Pole Barn Guru response:

“Thank you for reaching out to me, I’d be happy to assist in any way possible. Any photos would be appreciated, as well as the sealed truss drawings.”

And back to The Pole Barn Guru from the Building Official:

“Thanks for the prompt reply.

Attached is the sketch used to construct this building (no stamp, this sketch was hand drawn by the sales rep supplying the trusses).

Also attached are the Truss Design Drawings.

Also attached are a few photos of the building and the truss support at the wall line.

Get a Building PermitMy concern is the structural integrity of the 2-2×12 (separate, not fastened together as a beam) nailed into the side of the 4 x 6 posts at 8 ft. o.c.

The shear stress on the nails thru the 2 x 12 into the posts seems to be the weak point of the load path.

 I would expect an LVL beam set into notches or on top of the posts to carry the load.

 In addition, I do not see any lateral bracing of the walls, other than the metal siding attached to the purlins.

 I am looking to get a feel if this design is close to being adequate or if there is a real problem here with weak framing.”

I’m on the road today, so won’t be able to get more complete answers to you as quickly as I would like.

One problem I am seeing right away, the roof trusses are designed to be placed 2′ o.c. but they are 4′ o.c.

It appears wall height is somewhere around 16′ – would this be a correct guess?

Just a quick opinion – this building has some serious problems. In the end – my recommendation is going to be for them to provide engineer sealed drawings (wet stamps and signatures) to verify the building as built (or with numerous corrections) is adequate to support the imposed loads.

More later ~ Mike the Pole Barn Guru

And here is my more detailed response:

Here is a more complete list of issues/potential issues with the pole building:

I’ve used the wind speed (Vult) of 110 mph as listed on the truss drawing. I feel this is in error and it should probably be 115 mph. I also assumed an eave height of 16′.

Sidewall column footings need to be a minimum of 30″ in diameter in order to support loads as listed on the truss drawings (assumes soil bearing capacity of 2000 psf) and should be a minimum of 6 inches thick.

Provision needs to be made to prevent column uplift.

The columns at 8′ on center appear to be three ply 2×6 glulams – depending upon the manufacturer, they may be adequate.

It appears the wall girts are 2×4. Spaced 24″ o.c., it would take 2×6 #2 to adequately support the wind loads given the Code requirements for deflection.

While they do not have to be fastened together, the (2) 2×12 truss carriers are inadequate to support the loads imposed by the trusses. A (4) ply 2×12 #2 SYP carrier would be adequate and would be stressed to 95.6%. A 1-3/4″ x 11-7/8″ 2800f LVL would also work. Connections are going to be an issue here – I ideally like to see the carriers notched into the columns, as then uplift becomes the force to be reckoned with. Each truss is placing 5200# of force on the middle of the 8′ truss carrier span.

Other than the front endwall, the walls (if adequately fastened with the correct size screws) will carry the shear loads without the need for further bracing. The front endwall must resist 3771# of shear force – which is impossible to do with diagonal braces – as enough fasteners cannot be placed in the ends of the braces to resist the imposed loads. Plywood or OSB shear walls should be added at the corners.

My real concern is with the trusses. The drawings submitted show the trusses spaced every 2′, yet they are installed every 4′. The truss drawings specify a 2x6x12″ 1650msr bearing block to be applied to each heel of each common truss, yet they do not appear in the photos provided. Truss drawings specify bottom chord bracing to be every 2’2″ in lieu of a ceiling as well as continuous lateral bracing on the longest diagonal truss web.

All doors should be verified for the ability to resist the applied wind loads, else the building will need to be treated as “partially enclosed”, which is just going to compound the issues.

In my humble opinion, the best bet is for the building owner to hire a registered professional engineer to design fixes for his building…and get a building permit.

Building Plans

Plans, plans, plans….

sample building plansAs one might imagine, with about two hundred new clients contacting us every day, we have some conversations amongst ourselves which are frankly at the least – interesting.

I listened in on a discussion between Hansen Pole Buildings’ Designer Matt and Managing Partner Eric recently.

Matt, “I have a lead that the guy is asking for plans only. I assume we don’t do anything like this? I guess he bought a building from someone else and it had no plans.”

Eric, “Correct we do not sell plans only. Even worse that he bought something without plans….aka a lumber pile.”

I’ve spoken with thousands of clients about their pole building kit packages in the last decade alone. I consider most of them to be smarter than the average bear (yes, I confess to having watched Hanna-Barbera’s iconic cartoon character Yogi Bear). Which leaves me both perplexed and wondering…..

How in the world would someone end up owning a “lumber pile”?

As the greater majority of my adult life has been devoted to providing pole building kit packages to clients, the two keys to success (from a provider standpoint) are furnishing great plans as well as explicit step-by-step instructions. Without these two keys, the potential for a lumber pile becoming an actual building (at least as envisioned by the person who bought the lumber pile) would be pretty well exactly zero.

Here is my take on buying just pole building plans on the ‘net: https://www.hansenpolebuildings.com/blog/2011/08/buy-pole-barn-plans/

Shopping for a pole building kit package? Then please do yourself a huge favor – make sure any potential providers are capable of producing and providing for you building plans which are both Code conforming and exactly match what is being built. Every last board on the building should be shown.

And, while you are at it, see if they will provide a copy of the instructions for assembly. Even if one has to pay for the instructions in advance, it is a good investment.

Poor plans equals poor planning, and poor planning makes for unhappy results.

Read here to find out what great pole building plans are all about: https://www.hansenpolebuildings.com/blog/2011/10/pole_building_plans/