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Minimum Design Loads and Risk

Model Building Codes, such as IBC (International Building Code), offer minimum design loads for climactic forces such as snow and wind. As building permit issuing agencies adopt codes, within their scope they can establish minimum values for their particular jurisdiction.

Key word here “minimum” – least values a building may be designed for and still obtain a permit to build.

I have long been an advocate for structural designs above minimum requirements. All too often potential new post frame building owners have not had adequate consultative design recommendations enough to find out increases in structural strength are often achieved with minimal investment.

For an earlier article concerning this subject please see https://www.hansenpolebuildings.com/2015/11/bike-helmets-and-minimum-building-design-loads/.

From IBC Section 1604.5, “Each building and structure shall be assigned a risk category in accordance with Table 1604.5. Where a referenced standard specifies an occupancy category, the risk category shall not be taken as lower than the occupancy category specified therein.”

Balance of IBC Chapter 16, including Table 1604.5 may be perused here: https://codes.iccsafe.org/public/document/IBC2018/chapter-16-structural-design.

Buildings representing a low hazard to human life in event of a failure include agricultural facilities. In most jurisdictions, detached garages and shops are also considered to be a fit and these would be considered as Risk Category I. In many areas agricultural buildings are either permit exempt, or do not have to go through structural plan reviews and inspections. Read a very expensive story about an agricultural building using minimal requirements: https://www.sbcmag.info/content/9/design-load-reductions-risk.

Risk Category I buildings are designed to allow for an occurrence greater than minimum design loads of once in 25 years (or a 4% chance in any given year). In theory, all buildings in this category should collapse within 25 years of construction.

Sobering, isn’t it?

Shopping for a new post frame building and want yours to be last one standing when a storm of a century comes to visit? If so, I would hope whomever you are speaking with offers options of increasing Risk Category from I to II. And bumping up snow loads by 5, 10 or even more pounds per square foot and/or increasing design wind speed by a few more miles per hour.

If you are not offered these options – ask for them. I’d like to have your building be left standing!

This entry was posted in Pole Barn Design, Building Department, Pole Barn Planning and tagged IBC, snow loads, building risk category, building occupancy category, Risk Category I, International Building Code on July 28, 2026 by Rick Ochs.

My Response: Why We Need Building Codes

Due to our recent storms throughout the country, we thought it might be nice to revisit a blog about building codes.

My Response: Why We Need Building Codes

As promised, here is my response to the Coeur d’Alene Press article of December 5, 2017 (exactly as I wrote in the comments portion following the newspaper article regarding adoption of building codes):

I will first qualify myself – I attended the University of Idaho in architecture. I was a manager or owner in the prefabricated wood truss business for over 20 years. I’ve been a registered general contractor in four states, In 1987 I joined ICBO (they write the Codes) as well as ASAE (American Society of Agricultural Engineers) and was a sitting member on the committees which established the huge majority of the structural design criteria for post frame (pole) buildings. I have had the privilege of being involved in the structural design of nearly 20,000 buildings in every U.S. state. I am a contributing writer for Rural Builder magazine.

In my humble opinion – anyone who wants to “run bare” without Building Code minimum standards being applied to their new structures is out of their freaking mind.

The Building Codes are designed specifically to protect the safety and lives of those who occupy (or are in the vicinity of) structures. The Code requirements are ‘minimum’ standards, which are just scraping by – however something is better than nothing. For residential occupancies, the risk (under Code) is a once in every 50 year probability of the design loads for a given home to be exceeded! And yet there are some who would do away with even this minimal amount of protection.

I am not at all an advocate of governmental intervention, however only a fool acts as their own engineer. I deal, on a daily basis, with challenges posed from new building owners who have had under designed buildings constructed in jurisdictions which do not require structural plan reviews.

Mr. Tyler’s concern about homes having been built on unstable ground is not the fault of the Code, but the fault of the agencies which issued the permits. A geotechnical study should be done for the proposed site of any new structure – this allows the RDP (Registered Design Professional – architect or engineer) who designs the structure to have adequate information to be able to properly address foundation challenges, before they become foundation issues. The Code does not mandate engineered soils reports.

As to length of warranty provided by builders – an educated new building owner will look for a builder who offers an extended warranty. This, again, is not a function of the Code.

Having accurate information about snow loads is crucial to proper structural design. The 2015 edition of Ground Snow Loads for Idaho was produced by the Department of Civil Engineering at the University of Idaho. Based upon 31 more years of snowfall study than the previously used document – it appears Ground Snow Loads in Kootenai County should range from 43 to 100 psf (pounds per square foot) depending upon one’s location within the county.

Several factors go into calculation of Ps (sloped roof snow load) from Pg (ground snow load) including exposure to wind, is structure heated or not, importance of building, slope of roof and roofing material. In many instances the calculated Ps load is going to be higher than the currently accepted 40 psf. Will this add to construction costs? Yes. Will it help prevent failures and possible loss of life? Yes.

What is the value of even a single life?

Rather than throwing the baby out with the bath water, my advice is to require every single building to be designed per current Code to include plans which are sealed by a Registered Design Professional.

This entry was posted in Pole Barn Structure, Professional Engineer, Pole Barn Design, About The Pole Barn Guru, Building Department and tagged RDP, registered design professional, snow loads, geotechnical study on May 19, 2026 by Rick Ochs.

Asymmetrical Truss Configurations, Wall Framing, and Snow Loads

This week readers “Ask the Guru” about the possibility of designing an asymmetrical truss configuration, how to frame the exterior wall to the upstairs floor, and what the snow load of “these pole barns” is.

DEAR POLE BARN GURU: Can I design an asymmetrical truss configuration? We need a small stand on one side with an exterior wall and a retaining(basement)/exterior(2nd story) on the other side. Ideally its a 62′ span, center/peak 26′ from the shorter wall, 36′ from the pure exterior wall. I have a sketch attached as needed. JOSH in CLARKSVILLE

DEAR JOSH: Most certainly we can design and provide it for you. If it is even remotely structurally possible, we can do it – up to a 102 foot clearspan.

DEAR POLE BARN GURU: I’m building a 30×60 pole barn with a loft. The upstairs floor is 2x12x16’s. How do you frame the exterior wall to the upstairs floor? Right now I’ve drawn the posts at 8ft centers. Then framed in 2×6 walls between them to support the 2×12 floor. Is there a better cheaper way to to support the floor? Maybe not frame in the walls but run 2×12’s from post to post to support the 2×12 floor? GREG in CRESTWOOD

DEAR GREG: Our engineers would typically support your upstairs floor with beams attached to roof supporting columns. Depending upon imposed loads, these may be multiple plies of dimensional lumber, LVLs (Laminated Veneer Lumber) or even prefabricated wood truss beams. Any of these options may impact required diameter of column footings. Provided you have an appropriately thickened edge slab, you could frame between columns with stud walls to support your floor joists. Either of these options should be reviewed by the engineer who seals your building plans. You don’t want to end up creating a structural problem.

DEAR POLE BARN GURU: Hello, what is the snow load on these pole barns? Thanks RON in SAUGERTIES

DEAR RON: We engineer each building for snow loads applicable to your particular jobsite. We have designed projects for snow loads in excess of 400 psf (pounds per square foot), so we can handle whatever your needs are.

This entry was posted in Lofts, Lumber, Pole Barn Questions, Pole Barn Homes, Pole Barn Design, Roofing Materials, Barndominium, Constructing a Pole Building, Pole Barn Planning, Trusses, Building Interior and tagged snow loads, wall framing, Asymmetrical Truss Configuration, clear span trusses, truss design, loft framing, roof snow load on April 23, 2025 by Rick Ochs.

Minimum Design Loads and Risk

Key word here “minimum” – least values a building may be designed for and still obtain a permit to build.

For an earlier article concerning this subject please see https://www.hansenpolebuildings.com/2015/11/bike-helmets-and-minimum-building-design-loads/.

Balance of IBC Chapter 16, including Table 1604.5 may be perused here: https://codes.iccsafe.org/public/document/IBC2018/chapter-16-structural-design.

Sobering, isn’t it?

This entry was posted in Pole Barn Design, Building Department, Pole Barn Planning and tagged Risk Category I, International Building Code, IBC, snow loads, building risk category, building occupancy category on April 1, 2025 by Rick Ochs.

Effects of Snow and Wind Loading on Building Cost

Effects of Snow and Wind Loading on Building Cost

My premise, with clients, has always been I wanted their building (in an event of a catastrophic event) to be last one standing. This resulted in my clients often ordering above minimum code requirements for snow and wind loading.

My curiosity taking advantage of my available time, I decided to take a closer looking into effects of snow and wind loading on building costs.

In our example building – I will take it to an extreme and use a 42 foot-clearspan width, 60 foot length and 20 foot wall height. For most people, this will be more than sufficient to have two full stories in some or all.

Other features I included were:

All colored 29 gauge steel roofing and siding fastened with powder coated diaphragm screws 18” enclosed overhangs
Vented eaves and ridge
Drywall ready – ceiling loaded trusses with ceiling joists, commercial bookshelf wall girts
Integral Condensation Control (Dripstop/Condenstop) factory applied to roof steel Omnidirectional Housewrap
3000f Glulaminated Columns
2400f MSR wall girts, roof purlins and ceiling joists
All framing fastened with Simpson Structural Screws
Prefabricated roof trusses
Engineering
Delivery

With minimal roof loading (20 pounds per square foot ground snow load) and wind speed (110 miles per hour and Exposure B ) $36,365 (Read my ‘cliff notes’ for understanding wind exposure here: https://www.hansenpolebuildings.com/2022/06/wind-exposure-and-confusion-part-iii/)

Change to Exposure C for wind added one (1) cent per square foot. Increase design wind speed to 140 mph and Exposure C was 43 cents per square foot above basic price. This translates to an under 3% increase in investment – even though wind force being resisted was nearly DOUBLE!

I also took very same footprint, decreased eave height to 10’ and when wind went from 110 mph Exposure B to 140 mph Exposure C, investment increase was LESS THAN ½%

How about snow? (loads listed are Ground Snow Loads or Pg):

25 added 0.4%
30 added 0.8%
35 added 1.8%
40 added 3.4% (considering snow load is DOUBLED at this point)

Even TRIPLING snow load to 60 psf adds only 8.1%

We only want your new post frame building to be built once, so why not consider having it engineered to support just a little (or even a lot) extra. Protect yourself, your loved ones and your valuable possessions. When a ‘once in 500 year’ storm rolls through – you will be ready! Read more about 500 year storms here: https://www.hansenpolebuildings.com/2018/11/500-year-storm/

This entry was posted in Trusses, Barndominium, Concrete, Footings, Budget, Lumber, Pole Barn Design, Professional Engineer, Constructing a Pole Building, Columns, Pole Building How To Guides, Pole Barn Planning, Pole Barn Structure, Post Frame Home and tagged post frame design, post frame building costs, wind loads, snow loads, Post Frame Home on December 10, 2024 by Rick Ochs.

Frost Heave and Rodents, a Storage/House Combo, and Dead Attic Space

This week the Pole Barn Guru answers reader questions about prevention of frost heave and rodents getting in to a post frame garage, advice for a storage/house combo in Oregon, and how some buildings can have “dead attic space.”

DEAR POLE BARN GURU: I am concerned about frost heave and rodents getting into a post and frame garage. How high off the ground should the bottom girt be off the ground to prevent damage and frost heave and what is the best method to keep mice from getting in under the bottom girt. Should galvanized screen or maybe soffit metal be buried in the ground? Would pebble stone be a better choice along the building sides to minimize frost heave rather than gravel or clay soil? Your advice is appreciated, WALLY in KAKABEKA FALLS

DEAR WALLY: Bottom of your bottom girt (UC-4A pressure preservative treated splash plank) should be 3-1/2″ below top of your finished concrete slab on grade.

Here are a series of articles about what causes frost heave and how to avoid it:

Pole Building Structures: What Causes Frost Heaves?

Beat Frost the Easy Way…Post Construction Drainage

Preventing Frost Heaves in Pole Building Construction

Here is how to handle rodents: https://www.hansenpolebuildings.com/2021/03/rascally-rodents/

DEAR POLE BARN GURU: We are considering building a pole barn to store hay and equipment that also has an apartment area within. What would you suggest we build? We live in Central Oregon and we can get substantial snowfall as we butt up against the Cascade Mountain Range. We have horses and cows that we will be storing hay for, a tractor, two 4 wheelers, a couple of vehicles and two trailers. Thank you in advance for your assistance. JONI in BEND

DEAR JONI: One 4th of July we downhill snow skied Mount Bachelor’s summit before lunch, then hit The Deschutes River for white water rafting. We have provided hundreds of engineered post frame buildings to our clients in Oregon, so we know your area well.

Before getting into a snow load discussion, I would be remiss if I failed to share some pitfalls of adjoining living quarters to where animals are housed. Dust Rodents

Noise Odors

Fire separation – usually takes a two-hour firewall, meaning you have to go outside to go between uses. Cost of Insurance – fire potential is an issue Resale Value – appeals to a very small percentage of people, for reasons listed above. I would strongly encourage you to look at two individual structures. I will ask one of our Building Designers to reach out to you, to best assist you in design of your ideal building(s).

DEAR POLE BARN GURU: I work in commercial buildings a lot, that have similarities to pole barn design. Some are wood and steel, some are all steel framed. But none of them have spray foam, they’re either rockwool or fiberglass insulation. And ALL of their roofs are closed dead spaced with no venting at all. In lieu of your reply, how do they get away with this? Why can’t I emulate what they’re doing to some extent? Thanks again! DAVE in GALES CREEK

DEAR DAVE: These commercial buildings are utilizing what is loosely termed as “Metal Building Insulation”. This is typically a fiberglass batt, bonded to an air impermeable air barrier (blocks water and air). This facing must have an air permanence equal to or less than 0.02 L/s-m^2 at 75 Pa. pressure differential tested according to ASTM E 2178. All seams must be tightly sealed. This can be accomplished where roof purlins are typically every five feet and interior plane of underside of roof is not interrupted by members such as truss webs.

This entry was posted in Pole Barn Heating, Pole Barn Design, Constructing a Pole Building, Barndominium, Pole Barn Planning, Pole Barn Structure, Ventilation, Building Interior, Insulation, Pole Barn Questions and tagged rodents, shouse, equipment storage, frost heave, hay storage, fire separation, snow loads on November 29, 2023 by admin.

Roof Replacement, the next Steps, and Hurricane Codes

This week the Pole Barn Guru answers reader questions about replacement of a roof damaged from snow loads, gravel and concrete steps, and what measures are taken in Florida to prepare for hurricanes.

DEAR POLE BARN GURU: We have a 24’Wx52’L pole barn in Northern California and the 2022 winter snow load compromised the roof structure. The roof structure needs to be replaced and we’re looking for builder/contractor recommendations, that serve Grass Valley, CA. RUSSELL in GRASS VALLEY

DEAR RUSSELL: Usually whomever insured your building can provide references for contactors in your area who do this type of work. I would reach out to them first. Most contractors, however, are not interested in partial rebuilds, due to them then becoming liable for structural integrity of entire structure. More often than not, it becomes less expensive to bulldoze what remains and rebuild from scratch. Best of success.

DEAR POLE BARN GURU: This is my new pole barn wall on one side. It is smaller on the opposite side. What is the rule for gravel and concrete and where do I measure from? I am not planning on doing foam boards. Overwhelmed by the next steps, and a concrete plan…SEAN in CALIFORNIA

DEAR SEAN: Top of your concrete slab should be 3-1/2″ above bottom of pressure preservative treated splash plank. Measure downwards from this point for everything under slab.

DEAR POLE BARN GURU: For residential builds in Florida are there additional steps need to be taken due to hurricanes? LESLIE in BLOUNTSTOWN

DEAR LESLIE: We have provided close to a hundred fully engineered post frame buildings to our clients in Florida. All of these are designed to meet latest Florida Building Code requirements. We always encourage our clients to design to greater design wind speeds than minimum requirements (we want yours to be last house standing). All of our doors are wind load rated and most of our clients purchase their own windows, in order to meet Code loading.

This entry was posted in Concrete, Rebuilding Structures, Building Interior, Pole Barn Questions, Roofing Materials, Professional Engineer, Constructing a Pole Building, Pole Barn Planning, Pole Barn Structure, Building Contractor and tagged roof replacement, snow loads, hurricane, concrete steps, pole barn floor, rebuild, Florida codes on August 2, 2023 by admin.

Condensation Control, Load Requirements, and A Sloped Site

This week the Pole Barn Guru answers reader questions about condensation control in Spokane, WA, the availability of a hipped roof design to meet wind and snow loads, and planning for a post frame build on a sloped site.

DEAR POLE BARN GURU: I’m in Spokane, WA– a semi-arid region, and I had a question about using metal roof panels with prefabbed integral condensation control, such as Condenstop, along with a double bubble reflective barrier. I have a few left over rolls of the reflective barrier that I can use and would only need to buy an extra roll or two for our prospective 36×36 post frame building. Would it be ok to use both without trapping moisture between the 2? Or, should I only use 1? Building will have continuous soffit venting on both eaves and ridge venting as well. The building will be used in-part to store food-crop and will be temperature-controlled during all seasons, and has drywalled ceilings. Therefore, I’d like to insulate to the max. Was thinking spray foam between the purlins and also fiberglass batts? MATT in SPOKANE

DEAR MATT: I was born and raised in Spokane, owned a house on Newman Lake until just a couple of years ago. In the 1990’s I was the area’s most prolific post frame builder – one year we erected over 200 post frame buildings in Spokane county alone!

Let’s look at doing this right, and not spend money just to spend money.

Spokane is Climate Zone 5A. 2021 International Energy Conservation Code requirements (IECC) are R-60 roof, R-30 walls

Roof: 16″ raised heel trusses, vent overhangs and ridge in correct proportion, roof steel with Integral Condensation Control, blow in R-60 of granulated Rockwool.

Sell your reflective barrier on Craigslist or Facebook Marketplace.

Walls: Steel siding, Weather Resistant Barrier (Tyvek or similar), 2×8 commercial bookshelf girts, R-30 Rockwool batts, well-sealed vapor barrier.

DEAR POLE BARN GURU: In your blog you state that hip roof style the strongest against high winds. as I live in tornado alley wind and snow drifting are concerns of mine and would like my building design to be highly resistant to these forces. Why can I not find examples of this roof style on your web site? Is the gambrel style the closest you come to this design? CARY in RAYMOND

DEAR CARY: Very few clients have been willing to make an extra investment into full hip roofs, explaining why our website has no photos of them (we do rely upon our clients to provide photos). We can engineer traditional (and most cost effective) gable roof designs with wind speeds in excess of 200 mph. Our Building Designers can incrementally adjust design wind speeds to allow you to make decisions to best meet your concerns and budget.

While most roof truss manufacturers meet Code requirements for unbalanced (drift) snow loads, we are one of few (if not only) building providers who also design roof purlins appropriately to resist these same loads. This typically results in purlins closest to ridge to be either more closely spaced and/or larger in dimensions.

DEAR POLE BARN GURU: We purchased property in north central Tennessee and are planning a post frame barn for a RV and SUV storage and then later adding a post frame home as our forever home. Building site has about a 5 – 10 degree slope. Can you recommend some reading material, books, articles, how-to’s that I can learn and start making some educated research and decisions? thanks. JEFFREY in PRAIRIEVILLE

DEAR JEFFREY: A plethora of options are available for sloped sites. They can be excavated to create a “walk-out” or “daylight” situation. I was faced with this situation on one of my personal buildings (albeit with a more extreme slope): https://www.hansenpolebuildings.com/2019/05/solving-massive-pole-building-grade-changes/
Sites can also be built up: https://www.hansenpolebuildings.com/2020/01/supporting-fill-when-considerable-grade-change-exists/
And there is always an option of “stilts” https://www.hansenpolebuildings.com/2020/03/stilt-home-barndominium/
For research, a great source of information is always to navigate to www.HansenPoleBuildings.com, go to SEARCH in upper right corner, type in whatever topic you are looking for information on (e.g. BARNDOMINIUM) and hit ENTER. Over 2000 articles are available, covering a broad myriad of subject matter.

Whatever route you do ultimately pick, fully engineered post frame is likely to be your most cost effective and energy efficient structural design solution.

This entry was posted in Post Frame Home, Steel Roofing & Siding, Ventilation, Building Interior, Insulation, Pole Barn Questions, Roofing Materials, Pole Building How To Guides, RV Storage, Pole Barn Planning, Pole Barn Structure and tagged condensation barrier, A1V, sloped site, wind loads, purlin spacing, dropstop condensation control, snow loads, Hipped roof on February 15, 2023 by admin.

Scissor Trusses, Attaching a Shouse, Attic Truss Space

This week the Pole Barn Guru answers reader questions about possibility of installing scissor trusses in upstate NY where there is a heavy snow load (80psf), a recommendation of whether of not to build a shouse and attach it to an aquaponic greenhouse, what the size of space an attic truss might provide with certain building height restrictions.

DEAR POLE BARN GURU: I am considering building a pole barn in upstate NY. We have a fairly heavy snow load (80psf). I was thinking about getting scissor trusses and spacing them out every 8′ and running purlins on edge. I am struggling to find the answer to whether this is possibly or not. Any help would be great! Thanks. DEVIN in DICKINSON CENTER

DEAR DEVIN: 2020 Building Code of New York State lists Ground Snow Loads (Pg) in Figure 1608.2, with the greatest area being 80 psf with an upwards adjustment of 2 psf for every 100 feet above 1000 feet above sea level. As an alternative, Pg may be determined using ASCE 7.

In most instances, placing columns every 10-12′ with double trusses directly aligned with columns and purlins on edge will be your most economical design solution. Scissor trusses may certainly be provided and used, however usually it will be less expensive to increase wall height to gain headroom.

DEAR POLE BARN GURU: My girlfriend and I are looking to start an aquaponic greenhouse system/farm. We are building a polycarbonate gable style greenhouse 30’x96′-120′ and we are needing to attach a post frame building to the greenhouse in an “l” shape off the shop end. We are/were originally looking to keep the house (4bed/3bath) one level roughly 50×100 splitting the post frame building 50/50 shop and house. But after looking at some of your projects we aren’t opposed to building a taller but shorter home with attached shop still 50×50. My question is in attaching the green house have you ever designed or worked with projects like this? CHRIS in FORT MADISON

DEAR CHRIS: I have not yet attached an aquaponic greenhouse to a post frame building. In all likelihood it can be done, however a question remains as to if it should be done. Aquaponic greenhouses have very high humidity levels (50-70% or more) while living spaces should be 30-50% for health and humidity. It might be prudent to have a small breezeway between, in order to not have to mechanically dehumidify your shop/house space. Otherwise, there is a distinct possibility of having condensation and/or mold/mildew issues within your residential spaces.

DEAR POLE BARN GURU: If I am building a 30×40 with 10 foot side walls, and I can only have a maximum peak of 17 feet, so roughly a 6/12 pitch, if I had attic trusses, how tall would the open space be in the attic room? If I can go taller and have a 8/12, or 9/12 pitch how tall could the open space be in attic? Thanks. KRISTI in SAGINAW

DEAR KRISTI: With an eave height of 10′ and a peak height of 17′ your roof slope would be 5.6/12 If your lower ceiling height was set to a finished 8′ you would have roughly 7′ of height dead center of your attic bonus room space – not tall enough to be considered as a usable room and height would decrease with slope of your roof.

If you were able to get a variance on height, it would obviously increase your space. We typically set a ceiling in bonus attic rooms at 7’6″ above finished floor height. At 8/12 this ceiling height would be roughly feet wide, at 9/12 roughly 10 feet.

This entry was posted in Pole Barn Questions, Shouse, Pole Barn Design, Constructing a Pole Building, Pole Barn Planning, Trusses, Ventilation, Building Interior, Venues and tagged attic truss loft, attic truss, greenhouse, aquaponic greenhouse, purlins, scissor trusses, snow loads on February 8, 2023 by admin.

Condensation Prevention, Sound Proofing, and Snow Loads

This Wednesday the Pole Barn Guru tackles reader questions about condensation prevention by placing foam board over the top of 2×4 purlins, options for sound proofing a post frame home, and if 2×4 flat purlins can hold a specific snow load.

DEAR POLE BARN GURU: I am planning a pole barn; the roof will have 2×4 purlins spaced 24″. I plan on putting 1/2″ foam board (faced on both sides) over the purlins with the seams taped. Then putting metal panels over the foam board. Will this be sufficient to prevent condensation from dripping within from the roof? JIM in MIDLAND

DEAR JIM: Good news and bad news…. while your proposed solution will likely take care of possible condensation issues, it is structurally unsound. Post frame (pole barn) buildings rely upon shear strength of steel roofing and siding in order to remain stable. When you add in even a half-inch gap of non-rigid material (foam board) between framing and steel skin, you greatly reduce (or eliminate) shear strength of your steel panels. Even if your building were to remain standing, shifting of steel panels with small diameter (#9 or #10) screws will cause slots to form around screw shanks, eventually causing leakage.

You would be best served to order roof steel with an Integral Condensation Control (read more on I.C.C. here https://www.hansenpolebuildings.com/2020/09/integral-condensation-control-2/) factory applied. It will be less costly, easier to install and not cause negative structural issues.

DEAR POLE BARN GURU: Afternoon! Thanks for all the great info in your blog. It has really helped me plan my new home. I have one question: I’m having a post frame home built and am wondering about soundproofing. The roof(s) will be steel directly on purlins with a radiant barrier in between. The conditioned space will have R-60 blown-in fiberglass above it so I’m not worried about that. What I am concerned with are the front and rear porches. The front will have a, 8″ shed roof porch and the rear will have a 16×16 gable-roof screened porch. Both will have finished ceilings, steel and knotty pine respectively. I’d like to be able to sit under either when it’s raining and it not be loud. What would you suggest I do to mitigate the drum effect in an uninsulated porch? I’ve thought about using rockwool batts, maybe mass-loaded vinyl, or even painting the underside of the steel with liquid rubber before the panels are screwed down. Any advice? Thanks much. PETER in HUDSON

I am pleased my information has proven helpful to you. I would consider one of two options – installing steel in these two areas over solid sheathing (OSB or plywood) with 30# felt or a synthetic underlayment, or using two inches of closed cell spray foam applied directly to underside of roof steel. Either of these should assist in mitigating sound.

DEAR POLE BARN GURU: In an area with a 50 p.s.i. snow load ground rating and trusses 4′ o.c., can 2×4’s 2ft. o.c. be laid flat for roof purlins? STEVE in WYOMING

DEAR STEVE: Maybe – this will depend upon numerous factors including (but not limited to):

Risk Category of building
Roof slope
Wind Exposure
Roofing material
Snow retention systems
If building is heated or not
Available grade of lumber

Ultimately this decision should be made by whomever your engineer is who is sealing your building plans. Special care should also be taken to insure adequacy of purlins in drift zones (closest to ridge), where purlins may need to be closer spaced, higher grade and/or larger dimension material.

Also – ground snow loads (Pg) are typically expressed in p.s.f. (pounds per square foot), rather than p.s.i. A p.s.i. of 50 would equate to 7200 p.s.f

This entry was posted in Professional Engineer, Insulation, Pole Barn Questions, Pole Barn Homes, Pole Barn Design, Roofing Materials, Post Frame Home, Constructing a Pole Building, Barndominium, Trusses, Ventilation and tagged purlin spacing, snow loads, drip stop, condensation, condensation prevention, OSB roofing, spray foam, steel over OSB on June 1, 2022 by admin.

A “Man Cave,” A Quote Request, and Snow Loads

This Monday’s PBG discusses a “Man Cave” designed with SIP panels, a quote request from Texas, and what our snow loads are for our buildings.

DEAR POLE BARN GURU: Considering a monitor style pole building with RV storage in center and living quarters on one side (loft in rear of building only) When RV is not in the center garage it would become the “Man Cave”.

I am considering timber frame trusses in only the center section of the Monitor Roof (likely 14′) and sip panels for roof insulation above trusses. Would make for pretty cool ceiling!!

I have scoured the internet for plans such as this – have you ever encountered or see a plan such as this? SCOTT in CAMBRIDGE

DEAR SCOTT: The reason you are not finding plans is because it would be both very cool and amazingly expensive. I have investigated SIPs panels a few times and found them to be prohibitively spendy. I intend to add onto our post frame shouse next Spring with a similar roof system in mind. To get the look I am after, I intend to build glulam trusses with purlins above them, closed cell spray foam insulation and most likely corrugated steel panels on the underside of the purlins. If you are intent upon a design such as you envision, you will need to invest in services of a Registered Professional Engineer to provide structural plans.

DEAR POLE BARN GURU: I am ready to build but I am in Texas. The plans were designed for traditional stick frame construction. Can you quote me from those plans? SOCRATES in McALLEN

DEAR SOCRATES: We most certainly can.

We would appreciate the opportunity to participate in your new home. Please email your building plans, site address and best contact number to caleb@hansenpolebuildings.com or dial (866)200-9657

Thank you. A Hansen Pole Buildings’ Designer will also be reaching out to you.

DEAR POLE BARN GURU: What is the snow load on the roofs of your buildings? KAREN in ALBUQUERQUE

DEAR KAREN: Every Hansen Pole Building is fully engineered to meet or exceed Code required snow and wind loads at the site the building will be erected upon. We have provided buildings designed for snow loads in excess of 400 psf (pounds per square foot). Providing us (or any supplier) with answers to these questions will assist in making your journey to a new building a smooth process: https://www.hansenpolebuildings.com/2019/01/building-department-checklist-2019-part-1/ and
https://www.hansenpolebuildings.com/2019/01/building-department-checklist-2019-part-ii/

This entry was posted in Building Interior, Budget, Professional Engineer, Pole Barn Homes, RV Storage, Pole Barn Questions, Pole Barn Design, Barndominium, Pole Barn Planning and tagged free quote, RV Storage, snow loads, Pole barn home, SIP panels, man cave on November 16, 2020 by admin.

Dry Set Brackets, Snow Loads, and Winch Boxes

The Pole Barn Guru continues to be inundated with reader questions, so we will be adding some mid-week PBG responses. First off is a questions about attaching posts to a square footing with dry set brackets, whether or not a Hansen Building can withstand a 40lb snow load (they most certainly can), and the use of winch boxes to raise trusses.

DEAR POLE BARN GURU: Can poles or square posts be attached to cement footings? 30 years ago we started working on a post and beam barn, cutting traditional joints, etc. Well that project was not completed you can guess why. Now we still have the footings that were going to have sills attached and the timber frame joined to that. My other half thinks we can essentially build a pole barn by bolting posts to footings. I have my doubts because as I understand it part of the stability of the pole barn depends on the integrity of the pole and its depth in the ground.

Thanks, MIMI in CATHARPIN

DEAR MIMI: There are dry set brackets designed for attaching post frame building columns to existing concrete, however our third party engineers will no longer certify them for use as they will not resist moment (bending) loads.

DEAR POLE BARN GURU: Do your buildings support a snow load of 60+ lbs per square foot? JARED in BONE

DEAR JARED: Every Hansen Pole Building is designed and engineered specifically for loading (wind, snow and seismic) conditions at your particular site. We have provided buildings with ground snow loads in excess of 400 psf (pounds per square foot), so your snow load should not be a difficulty. A Hansen Pole Buildings’ Designer will be reaching out to you for further information and to assist you with your new post frame building.

DEAR POLE BARN GURU: I am working with Mindi on my quote. I found info on using hand crank winches to raise preconstructed sections of the trusses and purlins. In the different articles, the construct a steel box that the winch is attached to and the box/winch is placed on the top of the poles. If I use wet set brackets, how much extra length is provided on the column? Would I be able to use the winch method with columns bolted into brackets? If I have a 24 ft span and 3:12 pitch, about how much would one truss weigh?
Thanks, LEE in HUNTSVILLE

DEAR LEE: Kudos for you to look to using winch boxes! Your savings in time (and safety) will more than pay to build a set of boxes. With wet set brackets you might want to have Mindi add two feet in length to your truss supporting columns, otherwise you will end up very tight for column above trusses. Cranking up trusses with purlins attached works equally well with either embedded or wet set brackets. Two pairs of trusses and all purlins for a bay will weigh somewhere under a thousand pounds.

This entry was posted in Pole Barn Questions, Constructing a Pole Building, Pole Barn Planning, Trusses, Footings, Professional Engineer, Columns and tagged dry set anchors, codes, winch boxes, dry set brackets, snow loads on October 13, 2020 by admin.

Multi-Story Pole Barns, Rubber Coatings on Posts, and Heavy Snow Loads

Today’s Pole Barn Guru answers questions about multi-story pole barns, rubber coatings on posts, and building for heavy snow loads.

DEAR POLE BARN GURU: I am looking into a multi-story pole barn with the top story being a home. I would need outside assess to the top story also. Do you build the pole barn or just send the materials. DEBBY in OJAI

DEAR DEBBY: We provide multi-story post frame (pole barn) building homes on a regular basis. Having outside access to your second floor is highly doable. We are not contractors in any state, we provide complete custom designs, third-party engineer sealed, all materials delivered to your site as well as complete construction assembly instructions for an average individual to successfully erect their on beautiful home.

DEAR POLE BARN GURU: Is there an issue with rubber coating a post with liquid rubber for first 6 feet of the pole (or coating the whole post even) and pouring concrete and slab together around the posts in pier-slab foundation style? ROB in JACKSON

DEAR ROB: As long as your proposed product is nonflammable and has no toxic off gassing then it should not prove to be an issue other than time and expense to protect a product having an ability already to outlast any of us. You should read: https://www.hansenpolebuildings.com/2017/12/will-poles-rot-off/. It would also behoove you to have your building’s engineer of record sign off on using your product of choice.

DEAR POLE BARN GURU: We are in an area of 120 – 150 snow load in the mountains of MT and want to error on the 150 load side when building our shed. The shed plan is 30×70 (2 RV doors) on the 30 side) with a 15×70 enclosed lean to (car garage door on the 15 side) that will have a car garage, workshop and storage room. Can we do a pole building with this size of shed and snow load or do we have to go stick built? KIM in BIGFORK

DEAR KIM: Post frame construction lends itself to high snow load requirements much better than stick built. We just finished designs for a building is Truckee California where snow load is 390 psf.

This entry was posted in Barndominium, Pole Barn Questions, Pole Barn Planning, Pole Barn Homes and tagged pole barn homes, post rot, post treatment, heavy snow loads, multi-story pole barn, rubber coating posts, snow loads on August 12, 2019 by admin.

A Problem Good Structural Engineering Could Solve Part II

Day 2 of a three part series by guest blogger Dr. David Bohnhoff, Phd. P.E., Professor Emeritus at the University of Wisconsin-Madison.

If you understand the information from yesterday’s blog, then you know that when someone tries to sell a farmer a building “designed to withstand a BALANCED snowload of XXX psf” that farmer should slam the door in the salesperson’s face. Obviously, that salesperson and the company he/she represents are not selling structurally engineered buildings. More often than not, they are selling a building that includes a truss that has been sized using methodology only appropriate for a small, residential building, and it is quite likely that not a single load calculation has been performed, and thus not a single component or connection has been properly sized/detailed for the loads to which it will likely be subjected. When you sell a structurally engineered building, you talk about the performance codes and standards that were used in its design. You talk about the code-specified GROUND snow loads in the area that were used IN PART to determine the complex load combinations required to properly engineer the building.

The fact that some companies are selling large agricultural buildings which are not fully engineered is shear lunacy and highly unethical if not criminal. When these same builders blame the failure of their buildings on a rare heavy snowfall, instead of their lack of providing a structurally engineered building, they are being deceitful/fraudulent. They also must take farmers and the rest of the general public as idiots. How else can you convince someone that a rare heavy snowfall is the culprit when the percentage of agricultural building failures due to a given snowfall is magnitudes greater than it is for other commercial and residential buildings in the same area. Along these same lines, how misleading is it to state something like “the snow loads exceeded those we used in design” when you never structurally engineered the building in the first place?

Over the years I have visited and read about an incredible number of agricultural building failures. I have seen piles of dead animals, and yet the problem with non engineered buildings has only gotten worse. Why is this you may ask yourself? Why does it happen in the first place? Why hasn’t the government done something about it? Why hasn’t the industry done something about it? Why don’t the insurance companies care? Where are the lawyers in all of this? These are all great questions with reasonable answers.

First, why has the number of agricultural building failures increased, especially at a time when the number of farming operations has decreased? Simply stated, larger and larger non-engineered buildings are being constructed. Unfortunately, there is a double whammy that comes into play here. As previously explained, larger buildings get hit with more complex loads, and if a building is not engineered to handle these loads, the probability of failure increases. Second, when you double the size of a building, you double the number of components in the building. In the case of a non-engineered building, you double the number of undersized components and/or connections. Thus a building that is twice as large has double the probability of a localized failure. The problem is that this localized failure can bring down a large portion of the structure if you are not careful. For this reason it is fundamentally important to incorporate mechanisms into large buildings that limit the extent of a progressive collapse (something that is absolutely not done in a non-engineered structure).

So as absolutely nutty as it is to put up a large building without structurally engineering it, why is it done? The answer is simple, there is no law requiring structural engineering due to the exemption provided in SPS 361.02(3)(e) AND builders who engage in the practice of selling and erecting non-engineered buildings can undercut the sales of those who don’t. The problem is, those who erect non-engineered buildings are putting people and animals in danger (extreme danger in many cases), and are sullying the reputation of the entire industry. Almost without exception, those erecting non-engineered buildings are small, local builders who (1) do not have a national reputation to withhold, and (2) don’t have deep pockets.

Come back tomorrow for Part III, the conclusion to Dr. Bonhoff’s expose on non-engineered buildings and why they fail under more than “normal” snow loads.

This entry was posted in Pole Barn Structure, Building Contractor, Rebuilding Structures, Pole Barn Design, Building Department, Constructing a Pole Building, Pole Barn Planning and tagged snow loads, structurally engineered buildings, agricultural building failures, heavy snow loads on April 5, 2019 by admin.

Placement of Sliding Doors, Extreme Snow Loads, and Custom Quotes

Today Mike addresses questions about placement of sliding doors, extreme snow loads, and quoting for a specific design.

DEAR POLE BARN GURU: I’m building a 32 wide 48’ long 14’ tall hay barn. 6×6 posts. Looking at my barn I have one post in the center and want two 16’ wide sliding doors to access my whole barn. Not sure if I should put them both on the outside and have one side slide behind the other or have one sliding door on the inside. Was worried about doors rubbing each other and scratching metal siding. Your opinion would be awesome. I can’t find any pictures online. Thanks. JOSH in BELT

DEAR JOSH: In answer to your question – most typical would be to use a double track system where sliding doors could be exterior mounted. Guides attached to center column can assist in keeping doors from rubbing upon each other.

Now my concern – having one endwall be all doors does not allow for wind shear loads to be adequately transferred from roof to ground. You should consult further with the RDP (Registered Design Professional – architect or engineer) who designed your building. If, by some chance, a RDP was not involved, you need to hire one now, as there exists a strong potential you are planning upon constructing a building doomed to fail.

DEAR POLE BARN GURU: Can a pole building be supplied to meet a 390 pound snow load? Will it work well in snow country? KURT in TRUCKEE

DEAR KURT: We can design a post frame (pole) building to meet any snow load you can imagine and perform admirably. Of concern would be keeping snow sliding off roof from accumulating along building walls and exerting forces against them (same issue with any building type). Your 390 pounds per square foot snow load works out to be nearly 15 feet of snow (https://www.hansenpolebuildings.com/calculating-loads/).

DEAR POLE BARN GURU: Do u quote from our design? JAMES in MT. HOPE

Get A Free Quote!

DEAR JAMES: If “our design” means dimensions and features you desire to have in your new post frame building, then yes. If “our design” means you have a set of plans you want us to quote materials off from, based upon how you or your RDP (Registered Design Professional – architect or engineer) think your building should be structurally assembled, then no.

We have found structural designs other than ours to almost universally be one of two choices. One of these choices would be under design, meaning if your building was built to those specifications it would stand a tremendous possibility of failure under less than design loads. Opposite would be over design. Usually over design will not be universal throughout a plan, instead one or more components are highly oversized or over specified adding to project cost, without adding benefit.

This entry was posted in Pole Barn Structure, Sliding Doors, Pole Barn Design and tagged building design, sliding doors, snow loads, heavy roof snow on January 21, 2019 by admin.

Elevated Floors, Snow Loads, and Species of Wood in Posts

This week the Pole Barn Guru answers questions about elevated floors, heavy snow loads, and what species of lumber posts are cut from.

DEAR POLE BARN GURU: We own a site that was fully treed so the soil is not so great. We are interested in doing a pole barn design however a few engineers recommend doing a pier and beam foundation. Do you have details that would allow the house finished floor to be elevated off the soils to create a typical crawl space? JOHN in AZLE

DEAR JOHN: A quick answer would be YES! Post frame (pole) buildings are ideal as homes over a crawl space. For more reading about this subject, please check out: https://www.hansenpolebuildings.com/2013/03/crawl-space/.

DEAR POLE BARN GURU: Can the Hansen pole barns be designed/built to 100 or 120 pound snow loads? CHUCK in WALLACE

DEAR CHUCK: Hansen Pole Buildings can be designed for any snow load you desire. Over my career I’ve been involved in many high snow load post frame buildings including ski resorts (https://www.hansenpolebuildings.com/2014/04/2014-winter-olympics/), in Glacier National Park, and right close to you in Wallace along I-90 – you may be familiar with a large blue building occupied by Spunstrand®.

DEAR POLE BARN GURU: What species lumber used for the posts 16 feet long? RICH in CHICAGO

DEAR RICH: Further reading regarding popular framing lumber species can be found here: https://www.hansenpolebuildings.com/2012/03/lumber-species/.

If you are talking about solid sawn timbers, they are most often Southern Yellow Pine (SYP) or Hem-Fir (primarily Western U.S.). With glu-laminated columns, most manufacturers use #1 SYP for pressure preservative treated portions and 1650 msr Spruce-Pine-Fir for uppers. For more information about msr lumber, please read https://www.hansenpolebuildings.com/2012/12/machine-graded-lumber/.

This entry was posted in Lumber, Pole Barn Design, Columns, Lofts and tagged posts, lofts, snow loads, elevated floors, wood types, species of wood posts on January 14, 2019 by admin.

Minimum Design Loads and Risk

Key word here “minimum” – least values a building may be designed for and still obtain a permit to build.

For an earlier article concerning this subject please see https://www.hansenpolebuildings.com/2015/11/bike-helmets-and-minimum-building-design-loads/.

Balance of IBC Chapter 16, including Table 1604.5 may be perused here: https://codes.iccsafe.org/public/document/IBC2018/chapter-16-structural-design.

Sobering, isn’t it?

This entry was posted in Pole Barn Design, Building Department, Pole Barn Planning and tagged International Building Code, IBC, snow loads, building risk category, building occupancy category, Risk Category I on August 22, 2018 by admin.

Insulation, Snow Loads, and Best Choice for Condensation

The PBG answers questions about insulation, snow loads, and best choice for condensation.

DEAR POLE BARN GURU: I am wanting to finish the interior of my pole barn and have an cathedral like ceiling. If I were to follow the trusses up to the peak with foam board Insulation and use 2x4s spanning between the trusses for support would there be enough air flo between 2x4s and metel to prevent condensation? If not is there a way. I have a ridge vent along peak and soffit vents on both sides of 1ft eves. Thanks for taking the time to answer. TIM in PORTAGE

DEAR TIM: To begin with, I will surmise you have either a rather typical Midwest style post frame (pole barn) building with trusses spaced every four feet on top of “truss carriers” (headers) or a building with single trusses widely spaced somewhere from seven to 10 feet on center.

foam insulation installation

You have a couple of choices – if you are going to utilize the existing intake (soffit vents) and exhaust (ridge vents) then a minimum of one inch of clear airflow must exist above the insulation. The high ribs of the roof steel will not provide adequate ventilation and there is really no way to create it after the fact. An alternative would be to seal the vents and use closed cell spray foam on the underside of the roof system. The closed cell foam should take care of any condensation concerns from the underside of the roof steel and it provides approximately an R 7 insulation value per every inch of thickness.

DEAR POLE BARN GURU: Can your building be designed to handle a 40# snow load? 24 x 30. JIM in WISCONSIN RAPIDS

DEAR JIM: Any snow load is very possible to be designed for, even those at high altitude snow ski resorts (including this one: https://www.hansenpolebuildings.com/2014/04/2014-winter-olympics/). Besides the snow loads in excess of 200 pounds per square foot at ski resorts, I’ve also provided post frame buildings in places like Glacier National Park, where the snow is so deep the park roads close for months in the winter.

DEAR POLE BARN GURU: I am planning on a 24x48x12 steel truss pole barn for vehicle/toy storage. Would you recommend a radiant bubble material under the metal to keep the inside of the barn for becoming a convection oven sitting in the hot Florida sun? Best wishes, JOHN in FLORIDA

DEAR JOHN: My first choice would be closed cell spray foam. While it is going to be more expensive, you will save greatly in labor as opposed to using a radiant reflective barrier. Radiant Reflective Barrier, installed correctly, might give you the performance you are seeking. If you do go with the barrier, single cell will perform pretty much as well as single cell. Buy six foot wide rolls with a tab. The tabs should have a pull strip over adhesive, which eliminates the need for taping seams. The six foot wide rolls mean fewer pieces to handle and overlaps to seal.

This entry was posted in Uncategorized, Insulation, Pole Barn Design, Ventilation and tagged radiant reflective barrier, Venting, insulation, snow loads on August 13, 2018 by admin.

My Response: Why We Need Building Codes

In my humble opinion – anyone who wants to “run bare” without Building Code minimum standards being applied to their new structures is out of their freaking mind.

As to length of warranty provided by builders – an educated new building owner will look for a builder who offers an extended warranty. This, again, is not a function of the Code.

What is the value of even a single life?

This entry was posted in Professional Engineer, Pole Barn Design, About The Pole Barn Guru, Building Department, Pole Barn Structure and tagged registered design professional, snow loads, geotechnical study, RDP on December 14, 2017 by admin.

Monitor Barns and High Snow Loads

Back in the early 1990’s, when I was building pole buildings, we had constructed a monitor barn for some clients in the Libby, Montana area.

For those who are not familiar with the term “monitor barn” it is a main gabled roof, with side sheds or “wings” on each eave side. The height of the wings is such as the high side of the wing is below the eave height of the gabled roof. Monitor style roofs are very popular in the horse community, as the wings can be utilized for horse stalls, tack and wash rooms, while the raised center affords height to allow for a second floor or loft for either living quarters, hay or other storage.

In today’s world the IBC (International Building Code) follows provisions to calculate sloped roof snow loads (Ps) from ground snow loads (Pg). To refresh yourself on how this works, please read: https://www.hansenpolebuildings.com/blog/2012/02/snow-loads/.

For applications in snow country, the IBC also requires roofs to be designed for unbalanced loads due to snow drifting. On gabled roofs, drifting can account for snow blowing from one side of a roof, forming a deep berm close to or at the peak of the opposite side of the roof. With monitor barns, drifting can also occur at the upper portion of the wings, against the taller gabled center.

Current roof snow design theory also takes into account snow sliding off from the upper gabled roof, onto the lower monitor roof.

20 plus years ago, things were far simpler, although not nearly as advanced technologically. For the area around Libby, it was generally considered good practice to design for the roof systems to handle a snow load of 40 to 55 psf (pounds per square foot).

Meanwhile, back at the ranch (actually back to our original story), a winter or two after this particular building was constructed – it snowed. A lot. Enough so it gave the appearance of Mother Nature actually making an attempt to use probability to create two exactly identical snowflakes. Eventually the snow got to be so deep on the upper gabled roof of the monitor barn so as to create an avalanche of snow sliding off the roof and impacting the lower wing roofs.

This impact was so great, it actually went through the roof steel – breaking several roof purlins on the way and creating some unique snow sculptures on the floor inside the building. Amazingly, the rafters supporting the wing roof did not fail!

This morning I have been working on the structural design of a monitor barn where the ground snow load is 120 psf. Big snow – glad I do not have to shovel it. The original design concept has the center gable 12 feet wide with an 18 foot eave height. Along each side is a 10 foot wide wing, which slopes from 11’4” to eight foot at the low side. There are some things which can be adjusted in this design, to reduce the investment for the client (as well as reducing the probability for structural failure).

By increasing the height of the wings, the price decreased and the useable space inside the wings increased! How is this? It reduced the height difference between the center gable and the top of the wing roofs – less area for snow to drift against and less of a distance for snow to drop from the upper roof. In this instance the perfect balance came with a wing eave height of 11’6”.

Adding snow breaks onto the upper gable roof also reduced the price. The 12 foot span truss cost was not greatly impacted by the added load from keeping the snow on the upper roof and the “whump” factor of snow sliding off onto the lower wing roofs went away!

With some flexibility in design monitor barns in snow country can be made more affordable and most importantly – safer.

This entry was posted in Building Styles and Designs, Budget and tagged pole barns, high snow load, monitor barns, snow loads on May 12, 2015 by admin.