Tag Archives: building codes

Oklahoma, Is it OK?

Oklahoma, Is It OK?

Last weekend my lovely bride and I attended an event hosted by her first husband’s sister and her husband. Event purpose was to celebrate this couple’s upcoming 40th wedding anniversary.

Adding to this fun, at least for me, was a new Hansen Pole Building being erected onsite (D.I.Y. husband doing some nice workmanship). Like most new construction this attracted a fair number of looky-lous who wanted to check everything out and offer their ‘armchair expert’ opinions.

One of these lookers was aforementioned husband’s brother, who (as I later found out) had his old pole barn collapse due to snow last Winter. Rather than contact us about a replacement building, he ended up buying a post frame building to be delivered from Oklahoma (keep in mind we are in Northeast South Dakota).

Now I happen to know these folks in Oklahoma who provided this kit package. I hadn’t visited their website in quite some time, so I went browsing.

Here are some things I found:

“Building codes and permits

In our recent annual post-frame construction industry survey, one of our questions to builders was about code enforcement in their areas. Of the 134 post-frame builders who answered this question, 55% said they have needed on occasion to change their construction to meet a code. Codes can be problematic if not clearly understood. Start with your local planning and zoning office or your local building inspector. They will be able to tell you the standards for your community.

Know the rules in your area:

  • Some cities will not allow a steel skin building – you must have a brick veneer.
  • Almost all residential areas will have a setback requirement, meaning the building must be so many feet from the property line.
  • Many neighborhoods have a restriction on how tall you can make the building.
  • Many areas want to inspect a building at each stage of construction, starting with the depth of the holes, then they will inspect the wooden framework, then the completed structure.
  • Some communities insist on bolting the trusses in place, adding hurricane clips, beefing up the top plate, digging the holes deeper and providing longer poles or adding gravel or a concrete footer in the hole.

Bonus Tip: Some local code expectations may seem over-engineered when it comes to equating cost with necessity. In our view, codes generally foster a better quality building and we have found it is best to give the inspector what he or she wants. Life, and your project, will go easier that way.”

Now I agree total with starting a journey to a new post frame building with visits to your local Planning  (https://www.hansenpolebuildings.com/2013/01/planning-department-3/) and Building (https://www.hansenpolebuildings.com/2013/01/building-department-checklist/) Departments.

What amazed me was “55% said they have needed on occasion to change their construction to meet a code”. Thinking back over nearly 40 years of post frame buildings, I can only think of two sets of circumstances causing a change in construction to meet Code. First – not submitting plans prepared by a RDP (Registered Design Professional – architect or engineer), second would be not having correct design criteria (snow, wind and seismic loads, along with frost depth) provided.

In my humble opinion, a majority of these builders who had to change their construction were probably not building Code conforming structures! Think about this if you are considering investing in a post frame building from ANY builder.

While some jurisdictions will not allow steel roofing and/or siding, I have yet to have any demand a “brick veneer”. There are numerous alternatives to steel, they just happen to be less economical and less durable.

Only insistence from communities regarding how buildings should be assembled comes from those who have prescriptive requirements for non-engineered pole buildings. Read about challenges of prescriptive requirements here: https://www.hansenpolebuildings.com/2012/02/prescriptive-requirements/.

Path to best value for one’s post frame building investment nearly always involves having RDP sealed plans. Make everyone’s life easier (you, your building kit provider, any contractors, as well as your Building Department) and insist upon only using RDP sealed building plans. Headaches saved, will be yours!

 

 

 

Builders Who Make No Upgrades in Twenty-Five Years

Builders Who Make No Upgrades in Twenty-Five Years.

Why?

We’ve Been Building This Way for 25 Years
In the event you happen to hear this from a pole builder – run away from them as quickly as possible.
Why?
Because every three years there is a new version of the Building Codes and often those new Codes come with changes in the way wind, snow and or seismic loads are applied to the building. New methods and materials seem to appear on the market so fast they make one’s head spin. Technology moves at a breakneck speed and to be doing things exactly the same for 25 years means your proposed erector is pre-internet in thinking!!

COREY in BILLINGS writes:
“Good Morning,
I was speaking to Rachel and she gave me your email to see if you might be able to answer a question for me. I hired complete a 50’x 80’ x 12’ pole barn here in Huntley, MT. The company showed up on the job yesterday and drilled the holes and started setting posts. Posts are 8’ center. They set the corner posts and maybe 6 sidewall posts and 4 endwall posts. The other posts were placed in the drilled holes and left for completion today/tomorrow. When I inspected the posts that were placed but not set (no backfill) I noticed that there was no footing or no cleats attached to post base to prevent uplift. When I questioned the owner of the company what he was using for footings he stated nothing added just solid tamped. I immediately called him and questioned his reasoning and got the I have been building these like this for 25 years. My question is on average what is the post load in psi on the 50’ x 80’ x 12’ pole barn with a 40# snow load? My soil has a bearing capacity of 2100 psi.”
In my humble opinion, you need to stop them immediately. Just because they have been doing them this way for 25 years does not make it correct.

Mike the Pole Barn Guru Writes:

Assuming a 40# design roof snow load and minimal design dead loads (usually 3.3 psf top chord and 1 psf bottom chord) gives a total of 44.3 psf X 8′ on center X 50’/2 = 8860# downward If they are using 6×6 posts (5-1/2″ nominal) they are placing over 42,000 psf on the base of the column!!

Roughly 21 times the soil bearing capacity.

Each post should probably have a concrete pad 30 inches or so in diameter underneath and at least 6 (if not 8) inches thick.

If I were you, I’d be requiring the building contractor to submit engineer sealed plans for your building to you (even if you have to pay for the cost). Otherwise you are pretty well hung out to dry.

Can I Build a Pole Barn on my Concrete Slab?

Can I Build a Pole Barn on My Concrete Slab?

I dove off from the turnip truck a long time ago, so I have seen a lot of strange things constructed over my nearly 60 year lifetime. Sometimes strange is good, usually not so good. What is remarkable are the structures which are constructed directly upon nothing more than a four inch thick concrete slab on grade. This includes post frame (pole barn) buildings.
Reader TIM in TYLER gets credit for triggering this article when he wrote:

“I have a newly poured 24 x 40 slab which I intended to build a convention style garage but budget restraints have rerouted me. I want to build a simply pole barn style carport with a metal roof. We have no snow to speak of in TX so weight should be no issue. I also want to do a storage area in the back like 12 feet x 24. Can I use the brackets and anchors I see to build on top of the slab? I’m thinking the loads points should be minimal due to a steel roof. I am in a rural area with no inspection requirements.”

Mike the Pole Barn Guru writes:
To begin with, in my humble opinion, just because one is going to build where there happen to be no inspection requirements does not mean one should exclude themselves from following the Building Codes. The Building Codes are only put into place after exhaustive discussions between construction professionals, Building Code officials, engineers, architects and product manufacturers. The Codes are perpetually changing, as new and better products arrive on the marketplace, practices are refined and more research is done into how buildings and materials perform.

While no snow may fall where your building will be located, one must still consider provisions for Code minimum loadings on the roof and the members below which carry them, including the concrete slab. Assuming a fairly standard roof overhang of say a foot, this leaves the perimeter of the slab being required to carry a load of over 13 tons! Using typical post frame construction, the point load at any one column could be over 4000 pounds, which could easily fracture just a slab on grade.

Standard post base brackets which you may see at your local hardware or big box store are not adequate to carry the loads to even an adequate concrete slab.

How I would do it?

I would use a concrete saw to cut out two foot by two foot squares at each column location, remove the concrete, auger holes as appropriately designed by the building engineer, set the columns in the hole per the plans then form and fill with premix around the top of the column to complete the slab.

If using brackets is your true desire, it may be possible to excavate under the floor at each column location and thicken the floor by pouring under the slab. It can be done, however it does take some effort.

Prefabricated Roof Trusses Part One

Prefabricated Roof Trusses – They can Make You or Break You

This article (written by yours truly) was published in the May 2016 Rural Builder magazine (https://media2.fwpublications.com.s3.amazonaws.com/CNM/RB_20160501e.pdf and begins on Page 26). Although the article is written towards post frame (pole) building contractors, it gives a perspective as to the challenges of ordering something as apparently simple as a set of prefabricated roof trusses:

I worked for, managed or owned roof truss manufacturing facilities from 1977 until 1999 – so we only ever had to operate under the pre-International Building Codes, which made our lives easy. Regardless of roof slope, exposure to wind, roofing material, whether a building was heated or unheated, the top chord live load (or roof snow load) was the same within any localized geographic region, with the exception of differences in snow load caused primarily by elevation changes.

When a client brought in a set of plans, we took on the responsibility to insure the quantity of trusses, roof and ceiling profiles, etc., were correct. We looked upon ourselves as being the experts – rather than the builder or building owner who was purchasing the trusses.

Walk in the door of a truss company today with a set of plans for a truss quote and the expectation is the purchaser has to be “in the know”, which I personally find counter intuitive, but it is the current reality.

As a broad generalization, today’s truss manufacturers are looking out for one entity, and it is not the person writing the check to pay for their product.

I am going to share some secrets which should both increase your bottom line as well as allow you to sleep soundly at night.

First – do not assume the truss company is going to do it right. It is better to take the more realistic position of, they will do it wrong. Wrong can result in an increase in the probability of a catastrophic failure, having to pay more than one should, or both.

Secondly – if you are shopping various vendors, the best price on the truss order might not be the best buy for your building.

A little sharing into how to make sure the trusses you order actually meet the required load conditions.

I am going to put in a plug here for Registered Design Professionals or RDPs. If you are constructing post frame buildings, or providing post frame building kit packages, and are not using originally RDP sealed plans, which are specific to the address where the building is being erected, you are seeing the light at the end of the tunnel and the light is a speeding train.

Maybe you have built or provided hundreds or even thousands of buildings and never had a failure. Trust me, the failure is going to come, and may have nothing to do with how the building was designed, but if an RDP did not design it you are placing yourself and your business at a tremendous risk.

On to important stuff, the Building Codes.

The IRC (International Residential Code) is a prescriptive code for stick frame buildings within limited parameters of snow and wind loads. It does not address post frame construction therefore all post frame buildings should be designed using the IBC (International Building Code).

The International Building Code (IBC) identifies the appropriate Ground Snow Load (Pg) to use on a building based upon its location. When jurisdictions adopt the IBC, they should also be designating the Pg value or values within their area of coverage. Some Building Officials are still rooted in the 1900’s and (contrary to the current Code) designate a Roof Snow Load, which often defies the Laws of Physics.

A case in point, not too many years ago, we provided the post frame building kit package for the Nature Center at the Cheyenne Mountain Zoo in Colorado Springs, Colorado. The Building Department gave the ground snow load as 27 psf (pounds per square foot), yet wanted 40 psf as the roof snow load. When our engineer called the Building Department to discuss this, the explanation given was, “The snow is just different here!”

Hmmm, ‘the snow is just different here’. Sounds pretty scientific. How about I give you some guidance as to what to really pay attention to, so your building is not only designed correctly to stay up but also how to save you some money. Sound good? Well, come back tomorrow to read Part II and get those answers… and a whole lot more.

Prescriptive Requirements

Larimer County, Colorado

I drive through the Fort Collins area about once a year. Other than the urbanized areas, the terrain is a classic example of Exposure C for wind (for a “fun” wind exposure story read https://www.hansenpolebuildings.com/blog/2011/11/wind_exposure/ or to get more technical: https://www.hansenpolebuildings.com/blog/2012/03/wind-exposure-confusion/).

weathered pole barnOne of our clients had been discussing with Hansen Pole Buildings Designer Lily a pole building to be located in rural Larimer County. The county had provided him with a sheet of “prescriptive” requirements for non-commercial, non-residential pole barns in the county.

I’ve railed in the past about prescriptive requirements from Building Departments, so I might as well keep up my soapbox rant (visit my prior rant here: https://www.hansenpolebuildings.com/blog/2012/02/prescriptive-requirements/).

For those who want to follow along, the Larimer County handout can be viewed at: https://www.larimer.org/building/pole_structure.pdf).

Let’s take a look at the “non-high wind” requirements.

Building is limited to 35 foot clearspan with engineered trusses. Columns are to be placed every eight feet. Footprint can be up to 3000 square feet. Maximum wind speed is 110 mph.

Now the catch in this is the statement in the handout, “All framing elements are to be designed in accordance with accepted engineering practice”. Which seems contrary to buildings utilizing the “basic handout design”.

With an eave height of 14 foot and a 4/12 roof slope, columns would need to be 6×10, IF diaphragm design is used, otherwise 6×12. I say “IF” because the handout makes no provisions for how to utilize diaphragm design.

In either case, all is well and good, except getting a solid sawn column larger than 6×6 in Colorado is a challenge unto itself.

The treated hold down cleat is not likely to provide sufficient resistance to uplift to resist 2512 pounds. A sophisticated engineering analysis would be required for proof. Read more about column uplift here: https://www.hansenpolebuildings.com/blog/2012/02/concrete-collars/

The 2×6 wall girts at 24 inches on center will work to carry the wind load (stressed to just under 96% of capacity), however deflection using the common framing lumber with a MOE (Modulus of Elasticity) of 1,300,000 is over in the deflection department by nearly 35%. It would take a MOE rating over 1,800,000 to meet the deflection requirements. (Read about girt deflection here: https://www.hansenpolebuildings.com/blog/2012/03/girts/)

The interior truss to column connection, must be able to withstand 4411 pounds of uplift force. Considering a Simpson Strongtie (https://www.strongtie.com/products/connectors/HRS-ST-PS-HST-LSTA.asp) HST2 7 gauge steel plate with six 5/8” diameter through bolts will only support up to 4835 pounds, it is not possible to imagine the two ½” carriage bolts (as specific in the handout) as being anywhere close to adequate.

To reiterate my basic premise: If a Building Department has PRESCRIPTIVE REQUIREMENTS for Pole Buildings – invest in an engineered building kit. It is less expensive to pay for the engineering and it guarantees a building which will be designed to actually meet the building codes!

Wind Speed: Really Cool Website

More buildings fail due to high winds, than high snows. To assist in avoiding new buildings meeting a similar fate as the straw house in “The Three Little Pigs”, the Applied Technology Council (ATC) offers a free web-based tool which finds location-specific wind speed using the GPS coordinate system.

This utility interpolates wind speeds to the nearest mile per hour based on the wind contours on the map using Google Maps as the platform. Specific sites can be located by using street maps or satellite images. Wind speeds are provided in 3-second-peak gust speeds for the three Risk Category maps provided in ASCE (American Society of Civil Engineers) 7-10 and for 10, 25, 50 and 100-year return periods. Access this free tool at www.atcouncil.org/windspeed.

The International Building Code design wind speeds are based upon 50-year return periods, and utilize the latest ASCE 7 requirements and wind speed maps.

The purpose of the “Wind Speed Web Site” is to provide users with a site specific wind speed using the GPS coordinate system. The reason this utility is needed is the spatial resolution of the wind speed maps displayed in ASCE 7 are not sufficient to determine a site specific wind speed. There are no reference city or town locations on the ASCE 7 maps and while county boundaries are shown, the resolution is affected when the maps are expanded large enough to distinguish the boundaries and approximate the city locations.

I, of course, had to just try it myself, so I entered my street address and clicked on the FIND radio button. This results in the latitude and Longitude of my address being displayed. Clicking on the FIND WINDSPEED radio button, gave me the wind information specific to my home. The 50 year MRI (mean recurrence interval) wind speed was 85 mph (miles per hour), which matches the code requirements in my area.

And, thanks to a very litigious population in the United States, use of the website information comes with a disclaimer:

“While the information presented on this web site is believed to be correct, ATC assumes no responsibility or liability for its accuracy. The material presented in the wind speed report should not be used or relied upon for any specific application without competent examination and verification of its accuracy, suitability and applicability by engineers or other licensed professionals. ATC does not intend that the use of this information replace the sound judgment of such competent professionals, having experience and knowledge in the field of practice, nor to substitute for the standard of care required of such professionals in interpreting and applying the results of the wind speed report provided by this web site. Users of the information from this web site assume all liability arising from such use. Use of the output of this web site does not imply approval by the governing building code bodies responsible for building code approval and interpretation for the building site(s) described by latitude/longitude location in the wind speed report.”

Certainly, having the ability to access this information will bring a higher degree of accuracy to designing buildings appropriately for prevention of failures due to wind. Especially important, will be to new building owners in areas which do not require Building Permits. There will be cases where the website and a Building Department will disagree on design wind speeds. Here, err on the side of caution, and design to the higher speed. I still think this is a pretty cool website.

OM – I Failed the Plan Check!

Life has now ended….nothing worse could ever happen…..ever….send my money back.

No – failure to get through an initial plan check is not a reason for suicide planning, or to be jumping up and down screaming.

Whether the building (or just plans) were provided by us, or anyone else – the first step is to get a copy of why the plans were rejected – in writing, and forward to whomever the responsible party is. In the case of Hansen Pole Buildings, send the checklist to us, not the RDP (registered design professional, aka engineer).

Why get it in writing? Ever play the “sit in a circle and whisper a secret to your neighbor” game as a child? The same applies to a plan check. Don’t leave anything to interpretation – get it in black and white.

While the great majority of plans sail through on the first try, it is not always the case. And why not?

Reason #1 – The client failed to verify their Building Code version and load conditions with the Building Department prior to ordering their building. I cannot speak for anyone else, but we DO REQUIRE our clients to verify this information.

Reason #2 – Failure to submit all required documents. Besides the building plans, a plot plan is a requirement. Where is the building located in regards to lot lines and other structures? If the plans are sealed by an engineer, the engineer’s calculations must be submitted as well. Engineer sealed truss drawings don’t come with the plans necessarily and the plans checker will kick the plans back without them.  Often, they come directly from the truss manufacturer.

Reason #3 – Didn’t discuss the proposed building with the Planning Department in advance. The Planning Department has the power of life and death. They could care less about how the structure is built. BUT – if your planned building is too tall, too large, too close to something they value and everything gets thrown into a blender on puree.  This is probably the most difficult of plan check failures to fix….after the fact. Heed my advice: don’t use the old adage “better to feign ignorance and beg forgiveness later”.  Trust me – this is not how to get your building to pass the plan check!

The least likely reason for failure to pass a plan check – is the structure itself, especially if the plans are sealed by an RDP. It is not just our engineers who are brilliant, it is engineers who have had to spend years of education and work experience to be able to perform their duties responsibly.

Why Design Criteria are Important

Last October Mr. W of Park County Colorado ordered a new pole building kit package from Hansen Buildings.

Just like every quotation or Invoice we prepare, it lists specifically the “Design Criteria” for his specific building.

Included in this were:

The Building Code and edition (every three years a new edition of the code is published, often with significant changes from the prior edition).

Flat Roof Snow (also known as Pf) – which is calculated by applying a series of factors to the Ground Snow Load (Pg). In some cases, in exception to the way the codes are written, a Pf value is stated by a particular Building Department.

Design Wind Speed in miles per hour (mph) as a three second gust, as well as Wind Exposure.

Allowable Foundation Pressure, as well as the general soils types which the given pressure would be applicable to.

Seismic zone.

Maximum frost depth of this design.

Thermal factor (Ct) and whether the building is heated or unheated. This factor is one of the influencing values in the calculation of Pf from Pg.

Occupancy Category (I, II, III or IV) – each of which corresponds to a factor which will influence the magnitude of snow, wind and seismic forces which the building much be designed to withstand.

Every quote we provide includes this statement directly below the design criteria:

You must confirm all code/design criteria with your Building Department prior to placing your order.

We recommend taking this page to your building department for them to verify all design criteria listed above.”

In ordering the building, the Purchaser must agree to the following as a portion of the terms and conditions:

Purchaser acknowledges verification/confirmation/acceptance of all Building Code, Plan and Design Criteria included on Instant Invoice. Information Purchaser has verified includes, but is not limited to: Applicable Building Code version, Occupancy Category, Ground (Pg) and Flat Roof (Pf) Snow Loads, Roof Snow Exposure Factor (Ce), Thermal Factor (Ct), basic Wind Speed (3 second gust) and Wind Exposure, Allowable Foundation Pressure, Seismic Zone and Maximum Frost Depth, as well as obtaining for Seller any unusual code interpretations, amendments or prescriptive requirements for non-engineered buildings which could affect this structure. If purchase is a non-engineered building, reasonable efforts have been made to assure structural adequacy, however no guarantee or warranty is made or provided by Seller as to whether this design actually meets with any applicable code or structural requirements. The ultimate responsibility for verification rests with Purchaser. Any costs due to changes or requests by Purchaser, Purchaser’s agents, or Building Officials to non-engineered plans will be borne by Purchaser, including any and all of Seller’s staff time for research, or any other reason, even if no changes are ultimately made. Staff time is billable at a minimum of $120 per person hour, with a one hour minimum.

 

Seller’s designs are all per specified Building Code and include the use of NDS Table 2.3.2 Load Duration Factors (Cd) as well as ASCE 7-05, Eq. 7-2 for slippery surfaces. Seller’s designs rely solely upon occupancy category and structural criteria for and at specified job site address only, which have been provided and/or verified by Purchaser. It is Purchaser’s and only Purchaser’s responsibility to ascertain the design loads utilized in this Agreement meet or exceed the actual dead loads imposed on the structure and the live loads imposed by the local building code or historical climactic records. Purchaser understands Seller and/or Seller’s engineer(s) or agents will NOT be contacting anyone to confirm.

 

Now if the above sounds harsh, keep in mind, we have provided buildings in all 50 states. There are over 7000 building permit issuing jurisdictions in the country and to keep absolutely current with any and all changes, is an impossible task.

Remember our good friend Mr. W from the beginning of this story? Mr. W’s county has on their website a form to complete, where they will verify the snow load criteria for anyone’s particular piece of property. While a pretty handy tool, it seems Mr. W did not use it.

He ordered a building, which we designed to the loads Mr. W confirmed he had verified. The plans were submitted and a permit to build was issued.

Now Mr. W has his building up and has called for final inspection. The inspector, in the field, notices the trusses are designed for a Pf of 50 psf (which matches what Mr. W ordered as well as the values on the approved plans). The problem…..the site is one where the flat roof snow load should have been 73 psf!

Mr. W now has a beautiful new building, which he cannot use. At least as it is presently built. The ultimate solution is going to involve a significant (as well as costly) repair to the trusses, as well as adding roof purlins between each purlin currently installed on the roof.

This is a case where an ounce of prevention (Mr. W having actually verified his loads as instructed) would have been well worth the pound of cure.

The question we sometimes get is, “why don’t you verify the loads for me?”  Come back Monday and I’ll tell you why.  Until then, think of the reasons we may or may not want to do this for you.

Building Codes: Wind Exposure C

We all know what Assume Means…

Bob is a builder in Northern California. He made a request for a quote on a building recently, via the Hansen Pole Buildings website.

The building he had in mind was to be 30’ wide x 80’ long. Bob told me the roof snow load was 100 pounds per square foot (psf) and wind speed 60 to 100 miles per hour (mph).

Bob called to discuss the project, which was to have one long sidewall open, so recreational vehicles, tractors and other equipment could be parked. I asked Bob how wide the openings between the sidewall columns would need to be – to which he replied 12’. Quickly doing the math, I suggested he might want to consider 84’ in length, as 12’ evenly divides into 84’. Bob liked that idea.

We discussed wind exposure. I asked Bob, “If you stand in the middle of the building site, with your arms parallel to the ground, and at 90 degrees to each other, and then turned in a circle, would the area between your arms ever be exposed to the wind?”  This would be Exposure C.   The alternative being a site which is protected from the wind on all sides, or Exposure B. Bob advised, once the three walls were up, it would be protected from the wind, because the “local winds never come from the open side”.

Somehow, I just do not think we were communicating.

For once, I listened to the little voice in my head and suggested to Bob that he give me the address of the site and I would call the Building Department to verify the loading requirements. While the building purchaser must ALWAYS confirm the code and loading information with their Building Department prior to placing a building order, I felt an ounce of prevention would be worth a pound of cure in this case.

Now Bob has been a registered contractor in California for over five years, in the area where the building will be constructed. The pleasant lady at the Building Department even guessed who he was, when I gave her the jobsite address. Obviously, he is known, and knows the area.

Well it turns out the design roof snow load was 60 psf, not 100. This will save Bob’s client thousands of dollars. The wind speed requirement is for 85 mph, however the entire county uses C for wind exposure.

There is a moral to all of this. Just because one hires an experienced registered contractor to construct a building, does not mean the contractor necessarily knows or understands the proper design criteria. Having the correct information on loads, saved the building owner thousands of dollars by using the correct snow load, and prevented a possible collapse from using an incorrect (and under designed) wind exposure.