Aluminum Roof Coating

  • Metal Roof Repair
  • Clear or brick red metal roof coatings
  • Use for sealing leaks in metal roof

Asphalt Shingle Roof Coating

  • Clear elastomeric roof coating
  • Asphalt shingle roof coating
  • Apply in below freezing temps

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How to Seal Chimney Flashing

The most common cause of chimney related roof leaks is the chimney flashing. In fact, if you have a roof leak in the vicinity of the chimney, it is most likely the chimney flashing. Chimney flashing is a 6 to 8 inch metal strip (usually lead or aluminum) used to seal the transition joint between the shingles and the chimney.

In some cases the chimney flashing was not installed, installed improperly or over time has deteriorated.  Seasonal heating and cooling can cause a chimney flashing joint to break and open the water tight seal.  The “old technology” method of repairing chimney flashing used a asphaltic based material over the suspected leaking areas.  The asphaltic base chimney flashing repair products were brushed or troweled on.

Unfortunately, the asphaltic material for chimney flashing repair is only a short term patch.  All asphaltic based chimney flashing patching compounds are not UV stable, and over time they degrade and crack on the roof.  This either opens the old leaking areas or allows new leaks to form. 

The first step to determining if the chimney flashing is the cause of the leak is to examine the chimney. The weakest points of the chimney are the top and sides. These are the areas that face the greatest UV and weather exposure, and therefore damage. You will notice the side facing the ground does not have chimney flashing.

You are inspecting the area for cracks or areas of water penetration. The brick and mortar will expand and contract with seasonal change. Since the mortar is not elastomeric, this expansion and contraction can cause cracks. In addition, mortar is very porous and absorbs water that will freeze in cold climates. This freezing and thawing will destroy the mortar joint causing a potential leak and degrading the structural integrity of the chimney over time. 

If there are cracks in the chimney use DynaSeal™ clear exterior elastomeric caulk to seal the cracks. You can also use DynaSeal™ clear elastomeric sealant for to seal and waterproof the brick and mortar.


Repairing Chimney Flashing Easily

Once you have completed the inspection of the chimney, take a look at the chimney flashing and shingles around the chimney. If the shingles around the chimney are cracked or have holes then repairing chimney flashing area is easily accomplished by sealing the shingles and the chimney flashing with DynaSeal™ clear elastomeric sealant. If you do not want unsightly black patches indicative of asphaltic patches on your roof use a clear elastomeric roof coating designed for asphalt shingles. 

Before applying the elastomeric roof coating, fill the cracks and holes with clear exterior elastomeric caulk. Next, following the manufactures instructions apply the elastomeric roof coating. Although the best time for repairing chimney flashing is in warmer weather, DynaSeal™ clear elastomeric sealant and caulk can be applied below freezing and even on a damp roof surface.