# What is the minimum roof slope for asphalt shingles?

What is the minimum Pitch/Slope of an Asphalt Shingle Roof? Shingles of all types need to have a slope to function properly. The minimum requirement is 2/12. The 2/12 number is rise over run or two units of vertical for every 12 units horizontal.
A.

### What should be the slope of a roof?

The minimum pitch for shingles is 1:6, which is equivalent to 4 inches rise to 24 inches run. The minimum pitch for a standing seam metal roof is 1:4, or 3 inches rise to 12 inches run. The minimum pitch for roll roofing is 2:12, or 2 inches rise to 12 inches run.
• #### What is the pitch for 3 on 12 roof?

It is the most common way in US and Canada to describe a roof's basic quality – slope or steepness. Roof pitch is represented in inches rise of 12 inches run. For example a “3 pitch” or “3 in 12 pitch” or “3/12 pitch”, all mean that the roof rises 3 inches, for every 12 inches of it's horizontal run.
• #### What is a fall of 1 in 40?

0.025 = 2.5% = 1 in 40 or 1:40. A gradient of 1 in 20 means there is 1 unit of fall (or rise) over 20 metres of run. Gradient ratios are dimensionless, so as long as the units of fall (rise) and run are the same, then the ratio holds true.
• #### How much of a fall do I need on a flat roof?

It is generally considered good practice for flat roofs to be designed to clear surface water as rapidly as possible. According to BS6229 & BS8217, flat roofs should be designed with minimum falls of 1:40 to ensure a finished fall of 1:80 can be achieved, allowing for any inaccuracies in the construction.
B.

### How do you find the slope of a roof?

The slope of your roof is the ratio of vertical distance (rise) to horizontal distance (run). Just write down the measurements you found. There's no need to simplify them. For example, if you find 4 inches of height with the tape measure at the 12 inch mark on the level, your slope is 4:12 or "4 in 12."
• #### What angle is a 12 12 pitch roof?

Roof Pitch
PitchAngleMultiply By
3/1214.0°1.031
5/1222.6°1.083
7/1230.3°1.158
9/1236.9°1.250
• #### How do you figure out a pitch of a roof?

The slope of your roof is the ratio of vertical distance (rise) to horizontal distance (run). Just write down the measurements you found. There's no need to simplify them. For example, if you find 4 inches of height with the tape measure at the 12 inch mark on the level, your slope is 4:12 or "4 in 12."
• #### How do you calculate a roof pitch?

The angle, or pitch, of a roof is calculated by the number of inches it rises vertically for every 12 inches it extends horizontally. For example, a roof that rises 6 inches for every 12 inches of horizontal run has a 6-in-12 pitch.
C.

### What is the ideal pitch for a roof?

The angle, or pitch, of a roof is calculated by the number of inches it rises vertically for every 12 inches it extends horizontally. For example, a roof that rises 6 inches for every 12 inches of horizontal run has a 6-in-12 pitch. That measurement is the number of inches the roof rises in 12 inches.
• #### What is a 12 by 12 pitch?

Roof pitch (or slope) tells you how many inches the roof rises for every 12 inches in depth. An Example of a roof pitch would be a “6/12 pitch” which means that the roof rises 6 ” for every 12″ inward towards the peak (or ridge). There are two suggested ways to measure a roof pitch.
• #### What is the use of a framing square?

Also known as a steel square, the Johnson framing square is a handy tool for carpentry. Its uses extend into framing and laying rafters and stairs. It can also be used as a straight-edge, finding and establishing right angles and marking cut-off work on widestock.
• #### How do you calculate rise over run?

Step 3: Use the slope to find a second point on the line. You will start with the y-intercept and rise up or down and then run left or right depending on the sign of the slope. Use the concept of slope being rise over run (rise/run) to determine how to use the slope to find your second point.

Updated: 16th October 2019