In this short video Joe Cochran demonstrates one way to measure your roof pitch to find the proper roof flashing.

When you’re in the planning phase of installing your chimney pipe it’s important to get on the roof and look for obstructions including bathroom fan vents, range hood vents, other chimney’s, electrical lines, etc to ensure that nothing will intrude on the area you want to run your chimney.

The last thing you want to do is cut a hole in your roof only to realize that there’s another vent that’s too close to your chimney causing a code violation.

Patching hole’s in the roof is never fun…

While you’re up there, you might as well measure your roof pitch.  There are several ways to measure your roof pitch, this is the method I most often used when installing wood stoves.

Here’s what you’ll need to get the job done:

Place one end of the level on your roof and hold the other end out until it’s level.  Then using your tape measure, measure the distance from 12″ mark on your level to the roof.

In my demonstration I get 5.5″.  This is known as the “rise” while the 12″ dimension is known as the “run”.

When speaking “roof pitch” you also place “rise” over “run”.  So in my example the rise is 5.5″ and the run is 12″ giving me a roof pitch of 5.5/12.

Since flashings cover a range of roof pitches I would choose a flashing that works with a 0/12-6/12 pitch roof.

Another common method that I didn’t demonstrate is to use a carpenters square that is at least 12″ long.

Instead of getting on the roof itself you can just climb up to the edge of your roof and hold the carpenters square up to the edge as shown in this diagram.

I hope this was helpful and if you have any questions while planning your chimney pipe installation feel free to call our chimney pipe experts at 866-667-8454.