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Anatomy Of A Chimney

Your chimney is more than just a stack of bricks and mortar; in fact, chimneys are surprisingly complex structures  with different parts and components that all work together to keep your fireplace burning safely and efficiently. By better understanding the anatomy of your chimney, you can begin to learn more about the purpose and function of the unique – and important – components of your chimney.

Anatomy of a Chimney - Seattle WA - Pristine Sweeps

Chimney cap

The chimney cap is a metal cover used to protect the top of the flue; chimney caps also often have mesh or wire sides as a way to keep animals and debris from getting into the flue. In addition to keeping out moisture, animals, and debris, chimney caps can also aid drafting by preventing downdrafts caused by wind.

Chimney crown

The chimney crown is the masonry or concrete slab that covers the top of the chimney; the chimney crown seals around the top of the flue pipe which the chimney cap then sits on top of. Well-designed chimney crowns will have an overhang of at least 2-2.5 inches to allow water to flow onto the roof instead of the sides of the chimney. Because they often take the most “direct hits” from the elements, chimney crowns are more prone to damage such as cracking.

Chimney chase

While the flues of masonry chimneys are surrounded by bricks and mortar, the flues of prefabricated or factory built chimneys are surrounded by the chase. The chimney chase is built around the flue to protect it as well as help make it more aesthetically pleasing; chimney chases are often made using the same siding or building materials as the rest of the home.

Chimney chase cover

If you have a prefabricated or factory built fireplace, your chimney will have a chase cover in place of a chimney crown. The chimney chase cover is a piece of metal – often a galvanized metal such as aluminum – that covers that top of the chimney chase and seals around the top of the flue. Because they are made out of metal, chimney chase covers may rust over time; staining on the sides of a chimney chase is often the first sign that the chase cover has begun to rust.


The damper is located at the top of the firebox between it and the flue and can be opened and closed using a pulley or lever when the fireplace is in use. Dampers should be opened when the fireplace is in use to allow smoke and gas to vent up the chimney; when not in use, dampers should be closed to prevent conditioned air from escaping.

Flue and flue lining

The flue is the metal pipes that create the venting system for the chimney; to protect the surrounding building materials, flues have liners made from materials such as clay tiles or stainless steel. Flues may need to be relined after damage or when a new fireplace is installed.

Learning about the anatomy of your chimney can help you understand the purpose and function of each chimney component. For more information about the anatomy of your chimney, contact Pristine Sweeps today!

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

All About Chimney Caps

Fireplaces and chimneys are surprisingly complex structures with a number of parts, all working together to maximize safety and efficiency. One of the most important components of the chimney is the chimney cap; chimney caps help protect your fireplace against animals, debris, and moisture entry.

All about Chimney Caps - Seattle WA - Pristine Sweeps

What is a chimney cap?

Chimney caps are metal covers that sit on top of the chimney crown, covering and protecting the top of the flue. Most chimney caps are made out of galvanized metal or stainless steel, while some homes have more decorative – yet still functional – caps made out of more expensive materials such as copper.

In addition to covering the top of the chimney, chimney caps also have wire or mesh sides. This design allows smoke and gasses to easily vent out while preventing small animals or debris from finding their way in.

Because every chimney is different, it is often recommended to have your chimney technician create or order a custom fitted chimney cap. While this may seem unnecessary with so many standard sizes available, a custom fitted chimney cap can ensure there are no holes and gaps in how your chimney cap fits. Likewise, ordering a custom chimney cap can give your more design or material choices than a store bought cap.

Why are chimney caps important?

While some chimney caps are designed to add a decorative flair or aesthetic touch to your roofline, most serve an extremely functional – and important – purpose. Below are three of the ways that chimney caps protect your fireplace and flue.

  • Animal entry: From birds to raccoons to squirrels, many small animals view a chimney structure as the perfect place to escape predators or nest with their young. With metal mesh or wire sides, chimney caps protect these pests from getting into your chimney structure; unfortunately, even a small hole or area where the cap does not fit properly can be enough for an animal to get in.
  • Debris: Think of everything you clean out of your gutters each year: twigs, leaves, blowing trash like plastic bags, and even small balls or toys. Now imagine all of that debris falling into your chimney! Debris in the chimney doesn’t just damage your flue; it can create blockages that cause gasses or smoke to back up into your home as well as dry out to create a potential fuel source for chimney fires.
  • Moisture: Rain, sleet, ice, snow, and even water from hoses or sprinklers can all damage your fireplace or flue if allowed into the chimney. By covering the top of the flue, chimney caps stops water from getting in and helps to prevent chimney leaks from occurring.

    Your chimney cap is one of the most important components of your chimney, protecting the fireplace and flue from moisture, animals, and debris. If you think your chimney cap might be damaged or simply want to make sure it is still in great condition, contact Pristine Sweeps today to schedule a chimney inspection!

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