I’ll take the easy one first.
If it is a commercial property or a five-plex where 90% of the roof is flat, it is a flat roof.
On a single family dwelling, this will not apply.
You only have to measure a roof if you plan on calling it a hip roof and there are non-hip roof features present. In most instances, a flat roof, a real flat roof not a metal roof over a screen room, will turn the home into a non-hip roof.
The whole reason for this measurement, if I read the studies correctly, is not to penalize individuals with dutch hip or dormers.
As I said in another thread, if it isn’t a true hip roof, it probably is going to end up being a non-hip roof after you measure it.
And, an update on my 3 1/2 year old son…he is still 100% determining the difference between non-hip and hip!
50 for 50 on the way to the RenFest today!
If you want to waste yur time measuring every home, go ahead!
If you have a home that has a gable end on one side and a gable end over the garage, you would more than likely have at least 25% of a non-hip feature and since that is greater than 10% of the total roof perimeter, it will be a non-hip roof. There is no need to measure it.
If you have a house with a flat roof at the back that is half the length of the entire rear portion of the home, that will be over 10% and again, no need to measure it.
It would be my opinion, and again, just me, that the only roofs you are going to have to measure are ones that have dormers or small dutch hips.
The pictures below are of the same house, but just pretend they are two different houses.
What type of roof is on the home, according to the form?
