Tag Archives: design loads

Structural Framing, the Cost of a Building, and “Base Supports”

This week the Pole Barn Guru answers questions from a Project Architect about the structural framing of a Hansen building, the cost of building plans with engineering, and if the Pole Barn Guru has advice for “base supports” for a wood floor in a Tube Canopy.

DEAR POLE BARN GURU: I am a Project Architect with some questions. Do you provide some type of laminated header around the top for truss bearing as well? Are there purlins (wall girts) on both the inside (for the sheetrock) and outside (for metal siding)? I’m trying to make sure our footings, slab and inside clearances are accurate. JIM in ALBANY

DEAR JIM: Hansen Pole Buildings are engineered with double trusses bearing directly upon notches cut into wall columns. This eliminates need for a header (aka truss carrier) around top of building for trusses to bear upon. https://www.hansenpolebuildings.com/double-truss-2/
Externally mounted wall girts typically fail in deflection https://www.hansenpolebuildings.com/2012/03/girts/
For structural strength against wind loads and being able to be insulation and interior finish ready, Mason has included what is known as “commercial bookshelf wall girts” https://www.hansenpolebuildings.com/2011/09/commercial-girts-what-are-they/.This method also leads to a superior interior finish when gypsum wallboard is applied. https://www.hansenpolebuildings.com/2019/09/11-reasons-post-frame-commercial-girted-walls-are-best-for-drywall/.


DEAR POLE BARN GURU: What would a complete set of plans with engineering cost for a 40′ x 120′ pole barn structure cost with a 14 ceiling height. Posts would be 12′ o.c. with girder trusses and purlin rafter roof framing. DENNIS in LAS VEGAS

DEAR DENNIS: Our engineers will only seal structural plans when we provide material package. Some materials they specify are proprietary to Hansen Pole Buildings and this is only way they can guarantee materials as specified reach jobsites. A Hansen Pole Buildings’ Designer will be reaching out to you to further discuss your building needs, or call 1.866.200.9657 for immediate service.


DEAR POLE BARN GURU: I am building a wood floor 17′ x 12′ to support a 3500 pound car under a portable tube aluminum and canvas car canopy (that will be mounted through holes in the floor directly to the ground underneath). The recommendation is base supports every 12 feet under floor joists every 2 feet, but they don’t specify the width of these two boards. One manufacturer’s picture appears to use 2 x 8 supports for 2x 4 joists. Can you suggest widths for these two items? ROBERT in WOODSTOCK

DEAR ROBERT: I have never been a fan of these canvas covered tube canopies – they do not have a track record of durability, if snow doesn’t collapse them, winds blow them away. Provided your site is level, it would seemingly be economically prudent to just place some gravel and call it a day. If floor framing members will be entirely supported by ground below, they could be any dimension, provided they are pressure preservative treated to at least a UC-4A (Ground Contact) level. Otherwise, you should reach out directly to your canopy’s manufacturer for their best recommendations.

Who is Responsible for Verifying Design Loads?

Who is Responsible for Verifying Design Loads by Contract?

Disclaimer – this and subsequent articles on this subject are not intended to be legal advice, merely an example for discussions between you and your legal advisor.

Please keep in mind, many of these terms are applicable towards post frame building kits and would require edits for cases where a builder is providing erection services or materials and labor.

DESIGN LOADS/CONDITIONS: Plan, drafting, engineering or calculation changes needed due to Purchaser’s failure to adequately confirm criteria in this section, or Purchaser’s desire to change building dimensions or features, will result in a minimum $xxx charge.

It is solely upon Purchaser to verify with Purchaser’s Planning and/or Building Departments, or any other appropriate government, or non-governmental agencies, the ability to construct purchased building(s) at location anticipated, as well as to apply for and obtain any needed permits. All due diligence to comply with any architectural or aesthetic covenants must be done by Purchaser, and Purchaser agrees to absorb any costs associated with compliance.

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), Wind Speed (vult or 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 or amendments.

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, 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 third party engineer(s) or agents will NOT be contacting anyone to confirm.

Dead loads specified on engineered roof truss drawings include the weight of the roof truss. Roof trusses are NOT designed to support ANY hanging loads or ceiling loads other than those specified as special truss loads in the Agreement. In the case of design roof truss bottom chord loads of less than five (5) psf (pounds per square foot) the bottom chord dead load may be sufficient only to cover the truss weight itself and may not allow for any additional load to be added to the bottom chord.

Roof truss top chord design loads of 5 psf (or less) are not adequate for roofing other than light gauge steel.

Seller recommends use of A1V (aluminum/single air cell/vinyl) radiant reflective barrier, an Integral Condensation Control (I.C.C. – Dripstop, Condenstop or similar), solid sheathing (with appropriate underlayment) or Purchaser applied 2″ or thicker closed cell spray foam insulation to help control roof condensation. 

In no case is Seller liable for any condensation issues. An I.C.C., when ordered, is manufacturer applied to roof steel panels only. Seller makes no representation of any R or U value for any insulation or insulation products supplied. In the event Purchaser opts to utilize snow loads, wind loads, wind exposure factors, seismic loads or ventilation of less than those recommended by Seller, or soil bearing capacities greater than those recommended by Seller, Seller and third party engineer(s) are totally absolved of any and all structural responsibility.

Any windows and/or doors provided by Seller are NOT wind-rated, unless specifically noted as such.

Any possible design responsibility for this building is null and void should any structural materials and/or construction be substituted, replaced, depart, deviate, or are otherwise altered from the Seller’s original building kit they belong to, including structural materials from suppliers not authorized in writing by Seller’s owner, or if building is constructed at an address other than as specified on plans.

Converting a Pole Barn to a Residence

Converting a Barn to a Residence

Reader MARK in PORTLAND writes:

“I have a pole barn structure that was converted to a residence without a permit. The slab is 4″ thick with a 4×4 skirt edge around the perimeter. Since the foundation is a pole (pier) system, does the slab edge (non-load bearing) need a thickened lip to extend below the frost line (18″ here)?”

Mike the Pole Barn Guru pole responds:

slab edge insulationWell Mark, as I am sure you are finding out, an entire plethora of issues now exists from the conversion being done without proper permits. Your slab issue just being one of many.

Homes are now required (in most jurisdictions) to meet with energy code requirements. This means you are going to (at the least) have to be adding some insulation below the finished grade of your building. This will eliminate the need to have a thickened slab around the perimeter of your building – which would not only prove to be an added expense, but also a royal pain to install.

I'd approach this challenge with the Frost-Protected Shallow Foundation method, which you can read more about here: https://www.hansenpolebuildings.com/2016/11/frost-protected-shallow-foundations/.

It may take having a RDP (Registered Design Professional – architect or engineer) on board in order to plead your case to the local permitting authorities, who could very well make your immediate future a miserable one should they become angered in regards to the change of use without a permit.

Your building itself could very well pose some other challenges. Most often these come from walls not stiff enough (from a deflection standpoint) to prevent the cracking of any gypsum wallboard surfaces. This is an area which can be looked into by the RDP you are going to hire (please nod your head yes).

Chances are excellent the roof trusses in your building are not designed to support a ceiling load, so you are probably looking at needing an engineered truss repair.

The siding should probably be removed and reinstalled with a housewrap underneath. In the event a dead attic space has been created, the attic area needs to be adequately ventilated to prevent condensation. You can find out more about adequate attic ventilation here: https://www.hansenpolebuildings.com/2012/08/ventilation-blows/.

Building Design: The Greatest Buildings Never Built

My mother used to have a saying, (watching my brother and I bandy about with many a sharp object), “it’s all fun until someone gets their eye poked out”.  In her stern voice, she was simply trying to make things safe for my bro’ and me.

You might have a totally sweet concept for your ideal dream pole building. An architect can design for you the most amazing project on paper, but some of the best ideas simply cannot be built. Every design must take into consideration elements, such as construction variables, materials, load weights, building codes, and cost which are necessary to bring paper drawings to life. In a Wall Street Journal article, some of the most amazing architects throughout history have designed buildings which were stricken with issues which made it impossible to construct their vision. See Wall Street Journal article at:

From Building Design to Reality

Even with today’s sophisticated programs, there are many designs with a fair amount of issues which create havoc when trying to move from a brilliant concept to the structural design stage.

With software programs, such as Hansen Buildings Instant Pricing, the pole building industry is able to bridge the gap between your vision and building reality. This proprietary program anticipates and solves issues during the pole building design stage, thereby reducing and eliminating headaches in the construction stage.  In 1956, if Frank Lloyd Wright had designed an electronic, 3D model of his proposed mile-high skyscraper, he would have been able to resolve its issues.  His challenges included the space and load bearing requirements to occupy a 528-story elevator system. With the proper software (and lots of money), Wright may have seen his vision come to life.

Construction software programs can not only design whole pole buildings, but they also allow for specific design of the most complex areas on any structure, such as roof trusses. If a roof fails, the whole building can fail, thereby making the roof truss one of the most important elements in the design process. Most design professionals agree elements such as roof trusses should be designed only by an experienced truss designer. Having the necessary experience, truss designers can take into consideration geometric volume (roof cavity) and the ability of truss components to perform given the building requirements.

Regardless if you’re designing a roof truss, a pole barn or a mile-high skyscraper, the vision and structural design requirements must harmoniously coexist before the first piece of material is cut.

Often I am challenged by folks wanting to design a pole building which may have possibly been done before, but not with the same design loads and dimensions.  And sometimes, I am put to the test to design a “pole barn” which looks nothing like any pole building you or I have ever seen before.  I rely upon solid calculations, design loads and a software system which can test them out for me.  If it isn’t solid and I can prove it on paper, I don’t want to see it built.  Just like my Mother taught me, “safety first”.