For many people, the process of selecting a chimney cap starts with this question: do I really need a chimney cap The truth is, yes, you do. If you've got an active chimney, you should have a chimney cap. The most basic reason for this has to do with fire safety. Whenever you use your fireplace, you create a lot of sparks. Most of them stay within the fire chamber or the base of the chimney, but some will reach the top of your chimney. If you don't have a chimney cap or screen to keep them contained, they could ignite your roof or any other nearby flammable materials.
Chimney caps are not, however, only important because of what they keep in but also what they keep out. Uncovered chimneys provide appealing nesting places for all sorts of small animals. Birds are the most common intruders, but it's not uncommon to find squirrels and raccoons in open chimneys. Such nests are dangerous because any kind of chimney obstruction can cause a smoke build-up inside your home, and the waste from these animals can harbor disease. And, of course, living above a functional fireplace isn't safe for the animals involved either. By capping your,chimney you're protecting both your family and your furry neighbors.
An uncapped chimney is also much more likely to suffer weather damage. Without a chimney cap to block rain and snow, water can seep into the mortar joints of masonry chimneys and cause bricks to become loose. Water can even soak into the bricks themselves, resulting in cracking as the water freezes and expands. Excess moisture also promotes mold growth and is one of the most common causes of unpleasant chimney odors. If you have a metal chimney, exposure to moisture can create even more serious problems. Water can destroy insulation, cause rust, and ultimately shorten the life of your chimney.
Even if you don't live in a particularly windy area, wind can still affect your chimney's draft. Strong gusts can cause the draw of your fireplace or stove to fluctuate rather than remain at a continuous, steady rate. This can cause downdrafts, a serious problem where the smoke from your fire is blown back down your chimney. Installing a chimney cap can block some of the wind and help your chimney's draft remain constant.
Now that you understand why a chimney cap is a necessary investment, you're probably ready to make a purchase. Before you can do that though, you'll need to identify what type of chimney and flue you have. That information is important because the kind of flue you have determines the kind of chimney caps you can use as well as the measurements you'll need to take in order to ensure your cap will fit properly. Read on to learn about the most common chimney constructions.
These chimneys feature single flues that extend above their crowns. They're among the most prevalent and come in square, rectangular, round, and oval varieties. The kind of chimney caps they can use is dictated primarily by their shape.
Metal liners are often used when an existing masonry chimney is unsafe or damaged. It's very easy to tell if you've got this kind of venting system because liners are softer and more flexible than another metal venting. Because of their design, metal liners can only be covered with slip-in chimney caps.
Multi-flue chimneys are exactly what their name implies; they are chimneys that feature more than one flue. They require top-mounted chimney caps regardless of whether their flues are extended or not.
This kind of chimney literally consists of a rigid metal tube and nothing else. They're particularly popular for venting wood-burning stoves. When it comes to capping, it's important to make sure you select a cap designed to work with a single-wall metal pipe.
This kind of chimney features two walls separated by open space and uses air to cool the flue. Because they are so specialized, they require chimney caps specifically designed for use with a double-wall air-insulated pipe. Ideally, you would use a cap manufactured by the same company as your chimney.
This type of chimney also has an inner and outer wall but uses insulation to separate the two. In some instances, the insulation is left exposed, while in others it is covered with a metal cap. Each type of double-wall solid-pack insulated pipe requires its own specific kind of chimney cap. And, as with air-insulated models, it's best to use a cap produced by the same manufacturer as your pipe whenever possible.
These function the same way as double-wall air-insulated pipes do, they just have three walls instead of two. They require caps specifically designed to fit triple-wall air-insulated pipes and, once again, it's best to use a model made by the company that produced your chimney.
Triple-wall solid-pack insulated metal chimneys feature three walls separated by insulation. You'll find models that leave the insulation exposed as well as ones that cover it with a metal cap. Your chimney cap choices are going to be limited to those specifically designed to fit your specific kind of pipe.
Standard chimney caps, with their economical weather and animal protection, are by far the most common. There are, however, several other types of chimney caps. Each is designed to address a specific chimney problem in addition to covering your flue opening. Below is information about the five basic kinds:
All chimney caps improve draft, but if you live in an area with extreme winds, a standard model may not be enough to prevent downdraft problems. In those situations, you may need a special draft-increasing cap to ensure that your fireplace vents properly. Draft-increasing chimney caps rely on Bernoulli's principle to create stronger updrafts. Their design forces wind around their tops rather than allow it through their openings.
The increase in air velocity decreases the static pressure above the chimney and causes a partial vacuum, forcing the smoke inside the chimney upwards. As a result, the harder the wind blows on this type of cap, the better your updraft will be. And it doesn't even matter which direction the wind is blowing. It is important to note, though, that these caps can't solve draft problems that aren't related to wind. If you have draft issues related to air inversion or the chimney top pressurization that can occur when your chimney is surrounded by tall objects, you'll have to seek out other solutions. Also, most draft-increasing chimney caps are designed to fit factory-built metal chimneys. If you're interested in using one for your masonry chimney, make sure you select one that can be used with an adaptor.
When you have draft problems that can't be solved by any other means, an electric draft-increasing cap might be your best option. These products act as both a chimney cap and a draft inducer and feature adjustable electric fans that allow you to directly control your draft. Just keep in mind that these chimney coverings are, due to their complicated nature, going to be much more expensive than other varieties. You should also have them installed by a chimney service professional.
If you've got an older masonry chimney with a loose-fitting, broken, or missing damper mechanism, heated or cooled air can escape through your chimney whenever your fireplace isn't in use. That translates into wasted energy and, of course, wasted money. Getting a chimney cap and damper combination may be the easiest way to eliminate this energy loss, particularly if you were already planning to get a chimney cap.
The dampers in these combo models function just like any other top-sealing model; the damper sits on top of your flue and is controlled via a cable that runs through the chimney and connects to a lever mounted to your fireplace wall. Opening and closing the damper is as simple as changing the position of the lever. A Note About Cap and Damper Combos: These caps are only available for square and rectangular chimneys. If you've got an oval or round flue you'll have to buy your damper and cap separately.
Most masonry chimney caps are mounted directly onto a chimney's flue or crown. Outside-mount chimney caps fit over the crown and attach to the body of the chimney. That makes them a good choice if you have multiple flues, oddly-shaped flues, or a poorly constructed crown. Outside-mount caps also provide some of the best weather protection because they cover the entire top of the chimney. Due to the wide variation in chimney dimensions, outside-mount caps are often made to order, but it is possible to find stock models. These are typically designed to fit a range of dimensions and are a much more economical option if you're interested in this type of chimney cap.
Flue stretcher chimney caps allow you to raise the height of your masonry chimney's flue by one or two feet while protecting your home from the elements and animal invaders. Some homeowners find their taller style more appealing than that of traditional caps, but the motivation behind creating this kind of chimney cover is purely practical. By elevating your flue you can solve some of the most common smoky fireplace problems.
How do you know if a flue stretcher would help you Take a look at the following scenarios and see if they sound familiar. Just keep in mind that even if your situation resembles the ones described below, you won't be able to use this kind of cap if you have a round or oval flue; they're only available for square and rectangular chimneys.
Smoke sometimes comes back into the room when you've got a fire burning. Downdrafts can be caused by a variety of different things, but if your chimney is below your roofline and there are structures blocking the flow of air to your flue, your problems may be caused by insufficient flue height. When trees, other parts of your home, or nearby buildings are taller than your chimney, your chimney may fail to develop an ambient updraft and smoke can be forced back down your chimney. A flue stretcher can help in this situation if raising the height of your flue a few feet will make it taller than the surrounding structures. 59ce067264