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  • Writer's pictureJustin McDaid

Waterproofing Your Chimney

Updated: Feb 28, 2022

In a battle between water and a chimney, water sealant may be the determining factor between a victory and a frustrating defeat!

As a chimney defends its' home from wind, rain, snow, and other inclement weather, the bricks can begin to reveal slight damage. Small cracks and minuscule holes may SEEM only cosmetic but can lead to very serious deterioration.

Over time and after enduring continuous beatings, mortar eventually softens and weather penetrates the outer layer of bricks. During colder months, water freezes in the cracks and holes. This continuous cycle further compromises your chimney.

This is why we recommend taking the extra step to waterproof your chimney.

The Chimney Safety Institute of America recommends applying a vapor-permeable waterproofing agent to masonry chimneys. This allows water to recede out but hinders it from entering the chimney. Paint or other non-vapor-permeable sealants trap moisture inside the chimney causing further damage.

Waterproofing your chimney is not a one and done service. We recommend re-applying water sealant every 3-4 years.

In extreme cases where there are gaps between bricks or missing mortar, waterproofing a chimney won't be enough to keep your fireplace safe. Repairing mortar joints may be needed to lengthen the life of your chimney.

A chimney inspection can help reveal what level of maintenance is needed. It is better for your home and wallet to waterproof your chimney than allow water to seep in and cause structural damage.

The best times of year to waterproof a chimney are during spring and summer. Warmer temperatures allow the sealing material to properly set and better protect the bricks.

Chimney Cap Protection

Some homeowners may consider installing a chimney cap as enough to protect their chimney. Because the top of the chimney takes on the brunt of the weather, this adds a significant amount of protection from water and other debris, but it is not completely sufficient.

Compare this to standing out in the rain. If you were to put a rain hat on, your head stays dry, but the rest of your body still gets wet. This is the same case for chimneys.

The equivalent of complete rain gear for a chimney is a chimney cap or chase cover, a sealed chimney crown, and a quality water sealant.

Is your chimney prepared to fight against the elements?


Signs of Water Damage

If you notice any of these signs in your home or fireplace, listen to the warnings and get your chimney inspected to prevent further damage. Avoiding the problems will make them worse in the future.

Moss or Plant Growth

Foliage growth of any kind between bricks is not good news. This means that there are cracks that allow enough moisture inside to provide a home for plants or moss.


If water is accessing your chimney, the top of your chimney or the inner lining can reveal rust stains.

White Stains

White efflorescent spots are typically made when water has evaporated from bricks. It can also be a sign that moisture has gotten into the flue which is NOT where it needs to be.

Water Damage on the Ceiling

Stains or bulges on your ceiling near your chimney may indicate water is entering your chimney.


Trust the Professionals

At FireTec, we believe in being proactive. As CSIA certified professionals, we provide high-quality waterproofing services to protect not only your chimney but your family.

Our team is passionate about helping you avoid costly, stressful repairs and lengthening the life of their chimneys!


Do you remember the last time your chimney was serviced? Have you noticed any signs of water damage?

Contact us for reassurance that your fireplace is up-to-date and your household is safe!

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