How do you properly flash a brick chimney?

Many issues on your residential roof stem from leaks occurring around your chimney.  The culprit is usually, but not always, the chimney flashing. Some of the issues with the chimney flashings that we see in the field are rusting or deteriorating metal and improper installation of the flashings.

If the chimney flashings are installed correctly and the metal is in good condition, it usually indicates that there might be an issue somewhere else in the chimney structure.  There could be loose, cracking or missing mortar.  The chimney chase cover on top of the chimney could be rusted out or damaged as well.  All chimneys are different, but these are the most common.

When installing a chimney flashing on a brick chimney there are 5 main components:

  • Cricket or saddle flashing located on the topside of the chimney
  • An apron flashing located on the bottom side of the chimney
  • Step flashing located on the sides of the chimney
  • Counter flashing embedded into mortar joint
  • Install Ice & Water barrier underneath the flashing for added protection against water intrusion

If you install a new roof, it is very important to replace the chimney flashing at the same time.  You want the flashing to last as long as the roof itself.  As always consult with a reputable roofing contractor in your area and I hope this helps with your next roofing project.