# What should be the slope of a roof?

Roof pitches for most housing types range from 4/12 (moderate) to 8/12 (extreme). Extreme slopes vary from 1/4 (nearly flat) to 12/12. (sloping down at a perfect 45-degree angle). Most roofs are between 6/12 and 10/12. Pitches below 4/12 are called shallow declines and those above 12/12 are called steep declines.

The formula for calculating roof slope is: degree of pitch = 180 - the fraction of total rise in feet divided by the fraction of total run in feet. So, if the total rise is 20 feet and the total run is 30 feet, the slope is 33/13 or about 2 5/8 degrees.

Fairly steep roofs are used on commercial buildings to reduce their cost. They are also used on some residential buildings to increase their value. Steep roofs are also called mountain roofs because they look like distant peaks.

Moderate roofs are used for most house plans with modest rises and runs. They can be as steep as 9/12 for very large houses on tall foundations. Flat roofs are used when it does not matter how much water drains off the roof because it will not cause any damage.

Low roofs are used for small houses on level ground. They usually have slopes of 3/4 to 7/8 degrees.

## What pitch is considered a steep roof?

A "steep roof" is defined by OSHA as any roof with a rise/run ratio greater than 4:12. (18.43 degrees). While most standard-pitched house roofs seldom surpass a 12:12 pitch (45 degrees), the landscape is occasionally distinguished by a design that harkens back to a time when far higher roof pitches were more popular. Such roofs are known as "steep" or "high-pitched."

The maximum allowable slope of a roof is generally calculated by dividing its rise by its run (height of one corner to height of another) and multiplying this number by 18.43. A roof with a rise of 10 feet and a run of 20 feet would have a slope of 5% (1 out of 20), which is equal to.05. This means that there will be 5 inches of drop for every inch of distance up the side of the building.

There are many factors that may cause a roof to be too steep, including age, material choice, climate, etc. Generally, the steeper the roof, the better it drains and the longer it will last. However, if a roof is too steep, it can cause flooding in low-lying areas around its base.

Roofs are designed with various rises and lengths to best use available materials and site conditions. For example, a flat roof can be useful when putting up solar panels, while a high-pitched roof might be preferred for keeping heat inside during cold weather.

## What is the most common roof pitch?

Conventional slope roofs are most common on residential roofs. This means the slope has a pitch of between 4/12 and 9/12 on most homes. Roofs with a pitch exceeding 9/12 are called steep slope roofs. They can be found on commercial buildings as well as some residential structures in areas where snowfall is frequent.

As you may know, sloped roofs are designed to allow water to run off their surface instead of flooding your home. For this reason, they usually have several low spots or gutter holes that help drain away any precipitation that does get into the space beneath the shingles. The size of these gutter holes depends on how much rain or snow you expect to accumulate on your roof; larger holes are better at draining more liquid than small ones.

There are two types of roof pitches: flat and ascending. With a flat pitch, the angle between the roof's lower edge and its upper edge remains constant, whether it is 10 degrees or 11 degrees. With an ascending pitch, the angle increases as you go up the roof. These terms will be useful when selecting a roof type for your home.

Now that you know what a roof pitch is, you should select one that is appropriate for the area where you plan to install it. Some locations may require roofs with certain slopes while others might not.

## Is a 9/12 roof steep?

The steepest conventional slope is a 9/12 roof pitch (36.37 degrees). A steep slope is defined as anything higher than a 9 on a scale of 12. A low-slope roof is one that slopes less than 3/12 - 1.5 degrees.

A medium-slope roof is one that slopes between 3/12 and 6/12 - 4.5 degrees. A shallow-slope roof is one that slopes 6/12 or more - 8.5 degrees.

A roof with a slope of 2/3 or greater is called a "high-slope" roof. It can be any degree but is usually between 5/8 and 1.

A roof with a slope of 7/12 or greater is called a "drop-slope" roof. It can be any degree but is usually between 1 and 3.

A flat roof does not have a slope; it can be any degree.

A house with a sloping roof is called a "gable-front" house. The term "gable-end" roof applies to a house with a sloping roof on either side, of which the front has gables (projecting triangular roofs) attached to it.

##### Daron Ovitt

Daron Ovitt is a professional building contractor. He has been in the trade for over 30 years and knows what it takes to get the job done right. His hard work, dedication, and attention to detail have made him one of the most respected members in his field.

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