2. LESSON OBJECTIVE
At the end of this lesson you will be able to differentiate
between pitch and slope.
Students are required to take notes throughout the lesson
3. QUESTION?
1. What do you think are pitch and slope?
2. Is there a difference between pitch and slope?
4. What is pitch/slope?
Both pitch and slope indicate the incline of a roof, expressed
as a proportion of the vertical to the horizontal. The term
“pitch” and “slope” are often used interchangeably, which is
incorrect. They do not mean the same thing.
5. What is Slope?
Slope is the incline of the roof expressed as a ratio of the vertical rise to
the horizontal run, where the run is some portion of the span. This ratio
is always expressed as inches per foot.
Slope Ratio
A roof that rises 4 inches for every 1 foot or 12 inches of run is said to
have a “4 in 12” slope. If the rise is 6 inches for every 12 inches of run,
then the roof slope is “6 in 12.”
6. What is Slope?
The slope can be expressed numerically as a ratio. The slope ratio
represents a certain amount of vertical rise for every 12 inches of
horizontal run. For example, a “4 in 12” slope can be expressed as the
ratio of 4:12. A “6 in 12” slope is expressed as 6:12.
Slope affects how roof systems are installed, including dictating which
type of roof-covering material can be applied.
8. What is Pitch?
Pitch is the incline of the roof expressed as a fraction derived by
dividing the rise by the span, where the roof span is the distance
between the outside of one wall's top plate to another.
A roof that rises 8 feet over a 24-foot span was said to have a “1 to 3”
pitch. If the rise is 4 feet over a 24-foot span, then the roof pitch was
said to be “1 to 6.”
9. What is Pitch?
The pitch can be expressed numerically as a fraction. The pitch
fraction represents a certain amount of vertical rise over the entire
span.
For example, given a roof with a rise of 4 feet and a span of 24 feet, the
pitch is “1 to 6” pitch, which can be expressed as the fraction of 1/6. A
“12 to 24” pitch is expressed as 1/2.
11. What is Pitch?
Using the illustration above and information we just learned about slope
and pitch, we can see that a 2:12 slope can be expressed as 1/12 pitch,
assuming the span is twice the length of the run. If the slope is 4:12, the
pitch for the 24-foot span is 1/6. If the pitch is 1/3, the slope is 8:12.
Remember, slope is expressed as a ratio and in inches per foot. And
pitch is a fraction derived by dividing the rise by the entire span.
12. QUESTION?
1. Which affects how you roofing systems are
installed, pitch or slope?
2. Which is more crucial to now when purchasing
materials for roof construction?
