Installing Tubular Skylights Determining Roof Pitch

DETERMINING ROOF PITCH

There are two different ways to determine your roof slope.

Method One

1. Take a carpenter’s level and place it against your roof as show in the illustration below.  Be sure it is level.

2. From the point where the level touches the roof, measure out 12 inches.

3. From this point, measure the distance in inches from the bottom of the level to the roof.

4. This will be the first number in the roof pitch.  The second number is always 12.

5. Use the chart below   (See Amount of Drop) to determine the amount you will need to drop the mark for the roof hole down the slope of your roof as indicated below.

Your “ROOF PITCH” is simply how far the roof drops vertically for every 12” of horizontal run.

Method Two

1. Use our roof slope chart (See Slope Chart) and visually determine the pitch of your roof.

2. Corresponding to that pitch is a drop length.  Drop the mark for the roof hole directly down the slope as indicated (See Roof Pitch Chart).