Chimney Flashing Seal | Prevent A Chimney Leak With Chimney Flashing Repair

Chimney Flashing Seal

We use FlashSeal Elastomeric Flashing Sealant to stop flashing leaks when possible.

The chimney flashing is the sheet metal installed where the chimney meets your roof. It completely covers the gap to create a watertight seal to prevent water leaks that can damage your chimney, attic, and roof deck. Normal wear and tear, frequent rain, snow accumulation, and improper installations are the most common causes of flashing damage.

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Bethesda Chimney’s certified professionals seal chimney flashing and provide other quality chimney masonry services, including custom chimney caps, crown repairs, chimney rebuilding, tuckpointing, and more for homes, businesses, and government buildings in Montgomery County, MD, Northern VA, and Washington, DC.

How Flashing is Installed by a Roofer*

Chimney flashing must be layered in a specific manner to avoid premature failure. Improper flashing installation is one of the most common causes of chimney leaks.

  1. First, we install a rectangular metal sheet under the roofing shingles. It is bent at a 90-degree angle, like an 'L,' along the edge of the brick chimney. This is known as Step Flashing, and it helps to deflect water away from
    the masonry wall.
  2. The next layer is the Counter Flashing, another rectangular metal sheet that overlays the Step Flashing. It is installed into the groove in the brick chimney to prevent water pooling.
  3. Finally, the last step is installing the Base Flashing. It is installed at the vertical surface joint in the roof and wrapped around the base of the chimney to prevent moisture intrusion.

The three flashing layers are caulked around the edges to create a watertight seal between the roof and chimney. It is also important to note that not all metal flashing is created equal. An installer may use galvanized steel, galvalume, copper, or other similar material. In addition, the durability of the flashing depends on material quality and workmanship.

*Bethesda Chimney does not install flashing - however we can refer you to a professional roofer we work with.

At Bethesda Chimney, our chimney professionals only use the highest quality materials when repairing  flashing.

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Signs Your Flashing Is Leaking

Unfortunately, many homeowners don’t realize the chimney flashing is damaged until a leak occurs. Due to its location near the roof, it is often mistaken for a roof leak. That's why annual chimney inspections are so vital. A chimney inspection allows us to spot flashing issues before it leads to more costly repairs. Watch for these common signs that indicate your chimney flashing may need to be repaired or replaced:

  • Gaps in the flashing caulk
  • Flashing has rust or corrosion
  • Water stains near fireplace or stove
  • Your bricks are discolored
  • Rotting wood in the attic or roof deck

Flashing Repair

Usually, the first area needing repair is the caulking that seals the flashing layers. Like mortar, caulking is also porous and will eventually wear away, allowing water to seep through. However, when caught early, this is an easy flashing repair because we can seal it with durable exterior roofing caulk or a FlashSeal product before it causes the metal to rust or corrode, requiring a complete flashing replacement.

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Chimney Flashing Repairs & Installation in Merrifield – Poolesville – Shaw, DC

Bethesda Chimney’s certified professionals provide expert seal chimney flashing repair & installation that will prevent future repairs from moisture intrusion. We serve residential, commercial, and government customers in Rockville, MD, Montgomery Village, MD, Springfield, VA, Silver Spring, MD, Centreville, VA, Reston, VA, Montgomery County, MD, Washington DC, and Northern VA. Call 301-969-4444 or 703-935-4444 to schedule a chimney inspection today!

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