The terms low-slope and steep-slope describe roof slope. Slope is how much a roof slants. A low-slope roof is one that has a slope of less than 3-in-1 2. This means that for every horizzontal foot, the roof level goes up less than 3 inches vertically.Steep slope means that the slope is 3-in-1 2 or more.

It is not hard to remember the difference between horizontal and vertical. Think about the fact that the sun sets "over the horizon." This will remind you that the horizon is flat. Horizontal means across or flat. Vertical means up and down.

To figure out roof slope, you need to know two measurements. These measurements are called the rise and the run.

The rise is the vertical distance. You can remember this is the vertical measurement because rise means to go up. It goes from the lowest point of the roof to the highest point. The run is the horizontal distance. It goes from the ver-tical line of the rise to the outer edge of the roof.