Defining Pitch

• Roof pitch is written in a ratio of inches. It is the number of inches of rise for every 12inches of linear space. For example, a roof with a "6:12" pitch rises 6 inches for every 12 inches of horizontal roof run. To help visualize this, consider the roof pitch to be like a right triangle. The angled hypotenuse is the roof, the horizontal leg is the flat roof run and the vertical leg is the rise.
  
  

Measuring Pitch

• You can measure your roof pitch from either the top or underside of your roof. To measure from the top of your roof, you would use a level and place that level at any point on the angled slope. Once you have steadied the level, measure out 12 inches. From that 12-inch point, measure down to the surface of the roof. If the distance from the level to the roof is six inches, then your roof slope is 6:12. You can also use this method while standing in your attic and placing the level against the angled roof interior. You would measure over 12 inches and then up to get the numbers you will need for the pitch.
  
  

Pitch Standards

• Aside from the ordinances passed by municipalities, there is no one single standard for roof pitch. But there are thresholds that contractors use to determine roof installation price. According to online roofing resource the Roofing Key, a low-pitched roof is anything between 2:12 and 4:12, a medium pitch ranges from 4:12 to 9:12 and anything from 9:12 up is a steep slope. The most common roof slope ranges from 4:12 to 9:12.
  
  

Considerations

• The steeper your roof pitch, the more expensive it costs to have it installed. Contractors require special equipment to build steep-pitched roofs, and the additional risk for the workers also figures into the price. But, according to the Roofing Key, a steeper pitch can be a good investment because the increased pitch removes water and ice from the roof more efficiently, which increases the life of the roof. The less pitch in a roof, the more that rain and ice can sit on the wooden roof foundation and rot the wood. Ice can also damage shingles over time. The increased pitch resolves these issues.