In a misguided effort to make things “easier” for potential building owners and builders, some Building Departments have prescriptive requirements for non-engineered pole buildings.
This means if someone walks in their Building Department’s door and wants to construct a post frame building, as long as the building owner (or builder) agrees to build to match these prescriptive requirements, they will be issued a structural permit. This is, of course, with a caveat of being able to meet requirements of other departments, such as Planning (https://www.hansenpolebuildings.com/2013/01/planning-department-3/).
WHY IS THIS BAD?
Doesn’t this save a lot of money, not having to pay an engineer?
Prescriptive requirements are often based upon, “we have always done it this way”, rather than having a basis in sound fundamentals of structural design. Every three years a new Building Code version is published, sometimes with sweeping changes in structural design as better research and new technologies (and products) have become available. Many highly qualified design professionals, including engineers, are involved in Building Code revisions.
A classic example of this came when International Building Codes were first adopted in 2000. Prior Codes did not have deflection criteria for wall members in those cases where members did not support a rigid finish (like plaster or gypsum board). New Code limits deflection for all instances. In order to meet these new requirements, in many cases, pole building wall girts can no longer be installed “flat” on wall column exteriors.
Many times materials are included in prescriptive requirements doing nothing but causing more work for whoever is actually doing construction, as well as using unnecessary larger lumber members than what an engineer would have specified.
On occasion, these prescriptive requirements do not actually meet sound structural design! In my spare time, I have challenged more than one of these and gotten Building Departments to make changes, as their prescriptive requirements would have resulted in an under designed building.
Scarily….if you build to prescriptive requirements, and have a collapse, your Building Department is absolved from any structural liability!
If a Building Department has PRESCRIPTIVE REQUIREMENTS for Post Frame Buildings – invest in an engineered building. It is less expensive to pay for engineering and it guarantees a building be designed to sound engineering practice and actually meet building code requirements. Your bonus is those sealed plans are your “insurance’ – your building’s engineer is now liable for both safety and integrity of your new building as long as his or her plans are followed.