# What Does A 4 12 Roof Pitch Mean?

A 4/12 roof pitch indicates that the roof rises 4 inches in height for every 12 inches, as measured horizontally from the edge of the roof to the centerline.

This is considered a low-pitched roof, as anything under 3/12 is considered low.

Standard asphalt and composition shingles are usually acceptable for 4/12 pitch roofs, but it is important to read the shingle manufacturer’s specifications to make sure installing them on a 4/12 pitch won’t void their warranty.

A 4/12 pitch roof has enough slope for water runoff, but it may be too low for regions with heavy snowfall, which can put considerable weight on the roof’s structure.

## Is 4/12 A Common Roof Pitch?

4/12 is a common roof pitch, also known as 4 over 12, 4 on 12 or “4 in 12” slope, or in ratio 4:12. It is the most common residential roof pitch and has an angle of 18.43° degrees.

It is steep enough to shed water quickly and comfortable for walkable.

Standard asphalt and composition shingles are usually acceptable for 4/12 pitch roofs, but it may be too low for regions with heavy snowfall.

## How To Calculate Roof Pitch?

To calculate roof pitch, you can measure the rise and run of the roof, measure the rafter length or truss system in the attic, use a right triangle formula to calculate the pitch, or convert from degrees if it is known.

To measure the rise and run, you will need an 18- or 24-inch level, a tape measure, and a pencil. Place the end of the level against the bottom of a roof rafter and hold it perfectly level.

Measure 12 inches from one end of the level and make a mark. Then, measure vertically from this mark to the underside of the rafter. This measurement is then divided by 12 to get your roof pitch.

Alternatively, you can measure the rafter length or truss system in your attic. You can then find your roof pitch by dividing your rise by your multiplier (e.g. 48 ÷ 10 = 4.8).

If you know your roof’s angle in degrees, you can find its pitch by converting it to a slope and multiplying it by 12 to get its rise.

To convert from roof pitch to degrees, convert it to a slope first before finding its inverse tangent (or arctangent).

Overall, there are several ways to calculate roof pitch depending on what information is available.

## How Do You Figure A 4/12 Pitch Roof?

A 4/12 pitch roof is a roof that rises 4 inches for every 12 inches of horizontal length. This forms an angle of 18.5° between the horizontal section and the roof.

To calculate the pitch, you need to measure how many inches a roof rises vertically for every 12 inches of horizontal length.

The pitch can be expressed as a ratio (e.g., 4:12) or in degrees (e.g., 18.5°).

It can also be 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.

For example, if a roof has a rise of 4 feet and a span of 24 feet, then its pitch would be 1/6. A minimum roof slope of 0.25:12 is required for standing-seam metal roofs.

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