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What is Chimney Flashing?

For our service area of Seattle and surrounding areas, the rainy season begins now and will continue on through spring. Between the rain and the cool temperatures coming our way this winter, your chimney is in for some work. The chimneys work constantly while fires are burning, but they work year-round to keep water and weather out.

Keep Water Out With FlashingWhat is Chimney Flashing Image - Seattle WA - Pristine Sweeps LLC

Flashing is made up of many thin layers of metal, laid in a specific pattern in order to keep water out. It is used to reinforce the area where the chimney and roof meet–the weakest part of the entire chimney system, and most susceptible to water penetration. When flashing is missing or damaged, water has a direct route into seams and cracks that lead right into the home and chimney.

Water and Winter Damage

Once water has penetrated the chimney system, it can ruin masonry from the inside out. Because masonry is constructed of materials that react poorly with water, the entire structure is affected by water, and homeowners often can’t see it until it’s too late.
Water causes damages including:

  • Rusted damper assemblies, fireplace accessories, hinges, and handles
  • Rotted and ruined wood and wall coverings
  • Deteriorated firebox assemblies and central heating system
  • Stained and decayed exterior mortar (spalling)
  • Deteriorated flue lining system
  • Collapsed hearth support and chimney structure
  • Settlement

During the winter water damage turns to winter damage. The water then enters the masonry chimney system in the home and cools, then freezes, and expands, damaging the structure. When it warms up, the water melts and moves further into the damaged area, repeating this process until serious structural damage occurs.

Hire a Professional

You can avoid water damages by hiring a professional for all of your chimney needs. Schedule chimney inspections annually, so that a professional can get a look at your chimney in the areas that are out of sight. When a certified chimney sweep sees your flashing is shifted or missing, it can be corrected before major damage occurs and any damage can be repaired.

Only a professional should install flashing because it is a meticulous process that is often done incorrectly due to lack of general knowledge and experience. The flashing is laid specifically so that no nails are visible (for water to access), and placement differs based on the slant of the roof and the roofing materials. If this isn’t done correctly, it will not last and it will leak.

If your chimney sweep finishes a flashing installation and you see nails or a covering of tar or paint, then you have a problem. Many amateurs cover the flashing with other sealers in order to prevent water penetration when they haven’t completed the job correctly.

We have a long rainy season ahead of us here in Seattle, Washington, and it’s our goal at Pristine Sweeps that every household in our service area has a safe and efficient fireplace this winter. Talk to Pristine Sweeps to ask about our flashing repairs and installation. Call 206-574-8414 or make an appointment online.

By Aaron Woodward | Tagged with: Tags: , , , | Leave a Comment