Wind Mit question Flat roof on Hip roof

How would you calculate this flat roof on a hip roof? I’m thinking taking the total perimeter of the roof (longest lines) and the the 3 sides of the flat roof as non-hip feature to calculate non-hip percentage.

That section looks like a mansard roof from here. I think that would fall into the “other roof” category


For wind mitigation purposes, if non-hip features are less than 10% of the total, then it still qualifies as hip.

A quick glance would make me believe the answer is “other”, but that was not the question.

Question is: how is the calculation made in this case?

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.