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How to Repair Chimney Flashing [Full Guide]

Having a chimney has many advantages. You can enjoy an odor-free kitchen environment. Your cooking session will be more pleasurable. Even your walls and tiles will be protected.

However, a chimney comes with an additional maintenance cost. Be prepared to spend extra cash to install, repair and maintain your chimney. Among the extra burden, you will need to worry about is how to repair your chimney flashing.

What is a Chimney Flashing?

Chimney flashing is installed to make the chimney waterproof. This offers protection against water penetration, leakage, and roof damage. It also serves as weather-stripping for the chimney, keeping moisture away and saving energy.

They are usually made of metal or vinyl and placed at the junction of the roof and the chimney. If properly done, a chimney flashing can last up to thirty years.

However, there it will come to a time that a chimney repair will be necessary. How will you know when to repair your chimney flashing?

How Much Does It Cost To Repair a Chimney?

How Do I Know If My Chimney Flashing Needs a Repair?

If you observe any of the following signs, then it would be best to properly check if your chimney flashing is still in order and, if not, to consider repairing it:

  • Crack in the sealant
  • Water dripping from the chimney
  • Stains on the wall joining the chimney
  • The color of the bricks is gradually changing

So, if your chimney flashing is damaged, how do you repair it?

How to Repair Your Chimney Flashing

Repairing a chimney flash might not be an easy task, but it is straightforward, and you can do it yourself. You will need the following tools and materials:

  • Ply bar
  • Hammer
  • Ladder
  • Mortar Trowel
  • Flat Trowel
  • Broom
  • Knife
  • Mortar mix
  • Sealant
  • Chisel
  • Wire Brush
  • Scraper
  • Tin Snips

Active Leaks

If your chimney flashing is leaking, you may only need to seal it. But if it has worn out, you may need to replace it entirely.

Therefore, search for active chimney leaks. These are usually caused by small holes or gaps in the flashing that can allow water intrusion. If you discover any part of the chimney that causes leakage, then consider how to stop it.

  • First, clean the area surrounding the gap with a wire brush
  • Roughen the area with a scraper
  • Cut out a patch from the material in which the flashing is made
  • Fix the patch on the hole with roofing cement

Corroded Seals

If the flashing seal has corroded, you can renew it by taking the following steps:

  • Pull the flashing out of the mortar joint without removing it completely from the chimney
  • Chip out the mortal and sealant surrounding the flashing with a chisel and clean the surface with a chimney sweep brush
  • Wet the mortar spot with water, then apply fresh mortal
  • pull back the flashing and press firmly to seal
  • Finally, apply sealant at the edges of the flashing

Damaged Flashing

If your chimney flashing has been damaged beyond repair, you may have to remove it completely and install a new one.

  • Remove the damaged flashing and shingles
  • With the mortar mix and the roof sealant, install the base flashing
  • Install the step flashing, front flashing, side flashing, back flashing, and counter flashing
  • Apply the caulk to seal the flashing

The Take-Away

Repairing a damaged chimney flashing is technical, but you can do it yourself. If you have an active leak, you can stop it by patching it with the same material the flashing is made of. You can also renew a worn-out caulk. However, it would be best if you replaced a severely damaged flashing.

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