Wind mit examples

The first shows a home with a second floor. The blue lines are the perimeter(incomplete), the red is non-hip and the white is not measured.

The Second, third and fourth pictures are different partial views of a roof with a blue perimeter and red non-hip. Note that overlapping areas are not measured as part of the perimeter.

I hope this helps those that need it.

Thanks, John!


Perimeter features plus structurally attached non-hip interior features. That makes sense! Thanks.

Please clarify why the high hat second floor roof perimeter would not be measured as it is a hip design that will expose the attic cavity if removed.

Thanks for the info, John

It is not the perimeter.

I believe that an engineer would say different. When specifying roof perimeter i.e. roof deck attachment, the perimeter is a different nailing zone and is included on ALL exposed roof lines. Just a thought…

You would most likely be correct, on the plans. It is also highly likely the the whole second story would have the same specifications, but we are discussing the 1802 form.

[FONT=TimesNewRomanPSMT][size=2] A. Hip Roof Hip roof with no other roof shapes greater than 10% of the total roof system perimeter.
Total length of non-hip features: ______ feet; Total roof system perimeter: _______ feet
I don’t interpret that to mean the low roof perimeter only.
I know you teach this course and have more experience than I with this but I don’t read an exclusion in this.

My thoughts exactly. I still believe there can be more than one roof perimeter for multi-level roof systems. Not including the upper roof perimeter in the total perimeter, only hurts the client.

I also would include the second story roof in the total perimeter.

If you are not going to count the perimeter of the second story roof, why would you include the gable on the second story as non-hip? Either it exists as part of the total perimeter or it doesn’t. You can’t say that the gable is part of the perimeter and the rest of it isn’t. Doesn’t make sense, unless your goal is to give as few discounts as possible.

I know what people have taught in the various classes, but I also know they made it up. Until I see something in writing from the OIR, I’ll count all edges of all roofs as perimeter.

Thank you Mark, and I totally agree.

I have not seen any class that offers that way of doing the calculations.

A perimeter is a perimeter no matter what you believe :slight_smile: No offense intended. A male is a male a female is a female a duck is a duck acid is acid. 2 + 2 = 4 some things are fact not up for discussion any longer.,

Time to get an answer from the OIR creators of the from, don’t you think?
I’ll email them and post the response.

I have send a request for definition to OIR and will post the response.



No you did not???\


You did not really ask for that did you?

You expect those idiots to do what they should have done years ago. Ha ha ha ha ha. Never ever ever ever going to happen.

Mike, use your inside voice please.

Let’s see what the response will be.


Sry he made me spit my BBQ ribs across the floor :slight_smile: