Wind Mitigation confusion

Please help…I have tried everywhere to get answers for my questions but I just can’t seem to get a straight answer…In the pic below I have two different roof elevations the upper and lower. Concerning Roof Geometry, I am to measure the entire roof perimeter of the top and entire roof perimeter of the bottom, add them together and then account for the small gable in the upper perimeter?

Good question for wind MIT expert Dennis Bonner. I haven’t run into a home shaped this way yet for wind mitigation but I bet Dennis would call this a non hip roof since the lower sections run wind into a sidewall and soffits.

That’s how I’d write it up

Know Dennis - cool, hard working guy.
He refers me his mold stuff.
I’ll send it to him. :cowboy_hat_face:

I’d call it a hip if there is 10% or less of non hip features…
Measure it from around the perimeter of the home.

Hip & Non-Hip Roof Calculations

Hip Roof Calculation

A hip roof is calculated by the measuring the length of the non-hip roof roofs (document on the form).

The total perimeter is measured (document on the form). The total non-hip roof perimeters are then divided by the total roof perimeter. If the answer is less than 10%, then the roof is considered to be a HIP roof, and “A. Hip Roof” should be indicated on the form.


Flat (Non hip): 12+15+12= 39’

Total Perimeter: 45’+24’+10’+12’+15’+12’+20’+24’= 162’

Non-hip divided by total 39’ / 162’ = 24.07% or NON-HIP.

When measuring other roof features, include non-hip features that are not part of the perimeter, like the above picture of a Dutch hip roof and the sketch below.

When measuring the perimeter, measure around the roof as a two dimensional object, such as from an aerial view. The non-hip features are measured as 8 feet plus 8 feet (8’ + 8’ = 16’), which equals 16 feet.

Gable included in the non-hip calculations.

Be sure to include all non-hip roof shapes when measuring the non-hip features.

Do not consider roofs or porches or carports that are attached only to the fascia or wall of the host structure over unenclosed space in the determination of the roof perimeter or roof area for roof geometry classification.


+2 great info and reply @rlewis5