Moisture can enter the flue anytime it rains, without a chimney cap. This can cause water to get inside the attic or house as it runs down the brickwork. The moisture can damage your walls and ceiling. A chimney cap can stop downdrafts from entering the home.
Chimney caps prevent unwanted hazards from entering the chimney and keep sparks from escaping and causing roof fires. Without a cap, water, sleet, snow, and hail can enter your home and cause damage to your flue. Also, small animals or birds can enter the chimney and build nests that create a dangerous blockage.
As one of the biggest causes of a draughty home, it can make sense to block a chimney opening, especially for larger unused fireplaces. Fixing a draughty chimney not only makes your home more comfortable, it helps to lower energy costs too.
Just like gutters, exposed chimneys get clogged with leaves and debris. The water problems caused by an open chimney can be exacerbated by a buildup of leaves and trash in the flue absorbing moisture. It can also turn your chimney into a breeding ground for organisms such as mold, mildew, and rot.
Fire Safety
Chimney caps are often designed to also function as spark arrestors. This means that any stray sparks or embers that flow up your chimney flue will not pose a fire risk. This is as a capped chimney prevents sparks or embers from escaping, trapping them in a safe place until they go out.
The openings in the chimney cap screens are sometimes very small, and they can become clogged with creosote. Creosote is buildup caused by wood smoke and is not only deposited on the flue lining, it can also clog the mesh.
You should cap any unused chimneys with a flue ventilator. Flue ventilators can be found on our chimney pot page. The flue ventilator stops rain entry to the chimney but still allows a small amount of air passage for ventilation.
The average chimney cap costs $300, but often ranges between $75 and $500, depending on size, shape, and materials. The average chimney cap replacement cost is $300, though it can range between $15 and $1,000.
A damaged or missing chimney cap
If there's no chimney cap at all, the flue is vulnerable to incoming water that can damage the chimney liner, the fireplace damper and other parts and areas within your chimney system. Chimney caps can be repaired or replaced as needed.
When rain falls on your unprotected chimney, it flows right down the flue and into the house. Not only does this cause water damage, but it also creates a fire hazard.
Yes, chimneys need to breathe, even if they won't be used anymore. The vast majority of problems with chimneys are related to moisture, and that's the issue as regards ventilation. If there is no air flow in the chimney, moisture gets trapped and deterioration of the chimney structure will be accelerated.
In fact, you can lose 10 to 20 percent of the warm air from your home through your chimney's damper. Suddenly, your fireplace is increasing, rather than decreasing, your home's heating bills!
If the top of your chimney flue does not have a chimney cap, it is essential to have one installed even if you do not use your fireplace. Without a chimney cap, there is nothing to stop rain, snow, sleet, and hail from going directly into your home.
Our disused chimney cap cowl (aluminium) is designed to cap off unused chimneys and prevent rain, birds, leaves, and vermin from getting into the chimney stack. This chimney cowl is made from aluminium which is beneficial as it is a corrosive-resistant material.
There are two basic types of covers for the flue. There is the smaller, less expensive “Chimney Flue Cap” which only covers the flue opening, and there is the "Custom Sized Outside Mount Chimney Cap” which covers the entire chimney top and chimney crown.
Do I need a chimney cap if my chimney is not in use? Yes, capping an unused chimney is important to prevent moisture buildup, downdraughts and animal intrusion which can cause damage over time.
Capping is undoubtedly the best option when it comes to dealing with your unused chimney. Failure to secure proper chimney ventilation could damage your chimney and roofing.
Not having a chimney cap can lead to quite a few problems: Rain, sleet, snow, hail, and other precipitation will get in your fireplace. Raccoons, squirrels, bats, and other critters will get in your chimney. Sparks from your fireplace could float out and cause a fire.
In the UK, the average cost typically ranges from £100 to £400, covering both materials and labour. However, these costs can vary based on several factors, including the type of cap selected, the complexity of the installation, and the condition of the existing chimney.
Chimney caps are most commonly installed by two kinds of professionals: chimney sweeps and roofers. Both groups are familiar with the safety procedures involved with working on roofs, and they're typically well-versed in chimney cap sizes and styles to help you find what you need.
A properly constructed chimney crown that is well-maintained with annual inspections should last up to 50 years or more.
Just because a chimney was designed to breathe doesn't mean it has to breathe, and I have blocked off all of my unused chimneys without any issues. If you insist on letting it breathe then let it breathe using outside (unheated) air only.
Most DIYers with the right tools and safety equipment will be able to install a chimney cap themselves, though if the roof is too steep or there isn't enough room to safely maneuver, then it's a good idea to hire trained professionals to get the job done.
In fact, chimneys are designed to draw air out and expel it outside. This is so, when you light a fire, the smoke can be carried outside rather than blown into your home. However, when a fire isn't lit, warm air that's created by your heating system can be lost via the chimney.