Chimney Caps & Chimney Crowns: Essential to Masonry Chimney Maintenance
Proper maintenance of masonry chimneys extends past the brick work. Chimney caps and chimney crowns are both important for the longevity of your masonry and the safety of your home. Both caps and crowns help protect your masonry chimney interior and flue from precipitation, and the damage freeze and thaw cycles cause.
The chimney crown is placed atop the masonry chimney as a form of protection against the weather. As crowns withstand a lot of abuse, they need to be made out of a solid material; most commonly, chimney crowns are made of poured concrete and free from cracks and crumbling.
As its primary purpose is to protect your chimney, it should overhang the masonry by at least 2 inches. The top should gently slope away from the chimney opening, encouraging precipitation to run away from the chimney interior. The overhang prevents this water from running down the masonry, and a slight ridge build into the underside of the masonry further encourages the water to drip onto the roof rather than reach the masonry.
Chimney crowns do not cover the chimney interior. Chimney caps serve this purpose. Generally made of metal, they are installed just inside the chimney opening and extend well above the chimney to allow proper venting and draft. They prevent water from falling directly into your chimney, and also help keep out birds and small animals attracted to the warmth.
While most chimney caps are relatively simple, they are not always interchangeable. Chimney caps can affect your chimneys draft and certain styles work better than others with different vent sources.
For example, wood burning fireplaces or fireplace inserts produce creosote and other combustible solids. Not only will these accumulate in your flue, they will also build up your chimney cap. This is specifically a problem if your chimney cap has a protective mesh. As it accumulates, it causes draft problems that can make your fireplace unpleasant and unsafe.
Top Sealing Dampers
In addition to simple cap styles, you have the option of added functionality. Top sealing dampers, otherwise known as “Top Dampers”, serve the function of both cap and damper. They affix to the top of your chimney much like any other cap, but can be opened and closed to allow venting. These easy to use top sealing dampers are connected to a switch near the fireplace, and with a quick pull of a lever the damper opens and closes. They’re constructed to prevent small animals from entering the chimney when open while shedding most rain, and to seal tight against water and air when closed.
While these top sealing dampers are of particular interest in older homes where the original damper is missing or broken, they can be of great benefit to most homes. They increase energy efficiency by preventing heat loss and down drafts. Relatively simple to install, most homeowners are surprised by how much top sealing dampers can save them in energy costs.
Chimney caps and crowns are an important component of masonry chimney maintenance. If you have any questions about chimney caps, crowns, or top sealing dampers, contact a trusted chimney professional. And of course, if you’re in the market for a trusty chimney professional in the Washington D.C. area, we’d love to work with you to ensure your chimney is safe and functional.