(Gregory Andrulot) #1

If a ridge is located 4’ from one outside top wall plate and 16’ form the other with a height of 12’ would the pitch still be stated as 3/5 as the slope on each side of the ridge would be different. Also, what about a roof without gable ends where the ridge/peak is off center. Can pitch only be calculated when the ridge is centered and is a ridge required to calculate?

(Roy Lewis, CMI - North Florida Inspector) #2

3 Ways to Calculate Roof Pitch - wikiHow

(Randy Mayo, P.E.) #3

The roof pitch only applies to one surface at a time. Most roofs have the same pitch on all surfaces and some don’t. So you can have the front of the house with a 10:12 pitch and the back with a 4:12 pitch.

(Gregory Andrulot) #4

I am a little confused here. According to the training module “pitch” and “slope” are calculated differently. “Slope” is calculated as a simple rise over run based on inches with run always represented as 12 inches. This does apply to each side of the gabled roof as run is calculated off of distance from one edge of span to the point where ridge is set. “Pitch” was described as calculating rise over run based off of the entire span and can be represented as any reduced fraction. It was described in the module that the two terms “slope” and “pitch” are not to be used interchangeably.

Where I’m stuck is how can “pitch” be calculated if the roof’s ridge is off center of the entire span?

(Bradley K. Toye, CMI) #5

Use all references to “slope” (for each roof plane). That’s what we deal with. Slope vs pitch is often confused and interchangeable with a lot of training material.

(Kenton Shepard, CMI) #6

Most homeowners don’t know and don’t care about which term is used. I use “pitch” but describe it as rise per foot of run (ex. 4&12) because during all the years I was in residential construction, “pitch” was the term everyone I dealt with used. If you wind up in court, I doubt you’ll lose a case over a small technicality like this.