Chimneys are exposed to a lot more extreme weather than the rest of the house – rain, wind, snow, sun, and hot and cold temperatures – thus incurring a good deal of damage. This damage comes in the form of loss of insulation, cracks caused by freezing and thawing, leaks, and structural failure. These not only make the chimney system less efficient, but they can be a safety hazard if damage starts to spread to the rest of the house structure.

Here in Oregon the rainy season is coming soon, and waterproofing your chimney to prevent leaks and further damage is essential. Here are some tips for waterproofing your chimney.

Chimney Caps

Chimney caps keep rain and snow from entering the chimney and causing damage. A well-designed chimney cap can also keep animals and birds out of the chimney as well. They can serve as spark arrestors as well, preventing sparks and embers from floating out of the chimney and starting fires.

Chimney caps should be easy to remove, clean, and inspect, and should be made of sturdy, non-corrosive material.

Repair and/or Replace Any Cracked or Broken Masonry and Flashing

Masonry deteriorates quickly in extreme weather. Little cracks can turn into big cracks very quickly. It is important to take care of any damage right away with high-quality materials. Make sure the crown is in good shape.

The flashing is the seal between the chimney and the roofing material, and prevents any rainwater or other moisture from getting into the rest of the house structure.

Waterproofing Sealant

Brick and mortar are both made of porous material, which absorbs moisture and can crack in extreme weather conditions. Many products are made specifically for the purpose of sealing the chimney masonry.

It’s important to not use paint or other clear sealants, as they can trap moisture in the masonry and cause further damage.


If the chimney is located on the low side of the roof where water run-off is directed against the chimney, the installation of a cricket will afford additional protection against water leaking into the home. A cricket is a water deflector that serves to direct rainwater away from the chimney. Crickets are recommended on chimneys more than 30-inches wide and they are especially important on steep roofs.

Be ready for the rainy season! Don’t put off water-proofing measures. Do it now before the rain and cold are here.

To make sure the work above is done right, consult a chimney professional. We’re here to help. Contact us today.

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