When a F1 Tornado Hits Your Brand New Post Frame Building

Disclaimer – this is NOT a Hansen Pole Building

Nice new post frame building 26’ x 56’ finished on a Tuesday

Following day, same building is hit with an F1 tornado, with wind speeds measured at 104 mph (top end of F1 is 112 mph).

Look beyond building itself at surroundings.

Wind Exposure C is open to wind in one or more directions, for 1500 feet, with only scattered obstructions generally less than 30 feet tall in any direction. This would include building sites in flat open country and grasslands. Can you see ‘forever’ in one or more directions and your ‘forever’ does not include a body of water over a mile wide? You are Exposure C.

In all likelihood, this site should have had a building engineered (somehow I am doubtful an engineer was involved in this design) for Exposure C winds. This increases your building’s ability to withstand wind forces by roughly 20%.

Why did this building fail? Overhead doors were most likely not wind rated doors. Once doors failed, wind pressure inside increase by 1/3rd – causing blowouts as seen in photos.

How to avoid tragedies like this:

Build only from site specific engineer sealed plans. Engineering is an investment, not an expense. A good engineer will save more money than it cost to engage them due to efficiencies in material usage.

Order wind rated doors. Please read more here: https://www.hansenpolebuildings.com/2014/12/wind-load-rated-garage-doors/

Make sure to be realistic about your site’s wind exposure: https://www.hansenpolebuildings.com/2022/06/wind-exposure-and-confusion-part-iii/

Don’t be afraid to explore building to higher design loads than minimal Code requirements: https://www.hansenpolebuildings.com/2024/12/effects-of-snow-and-wind-loading-on-building-cost/