Protecting the top of your chimney from rain or snow going down the flue only makes sense. It's why you will find some chimneys topped with a piece of slate, and why you'll find plenty topped off with a metal cage-like contraption. But what is the right way to go? And why are they really necessary? How do you choose a chimney cap?
Chimney caps come in a variety of forms, but only a professional chimney technician knows exactly what a particular chimney system requires in terms of chimney caps.
The first important aspect in choosing a chimney is the durability of its material. A chimney cap is supposed to withstand rain, snow, and wind. Water will cause galvanized steel to rust in a short time. Stone caps will erode given enough time, and cracks and crevices will only accelerate its deterioration as the freeze-and-thaw weathering cycles take a toll on its integrity. The best choice is
a chimney cap made of Stainless Steel or Copper if you want the more aesthetically pleasing look. Manufacturers of these caps offer a lifetime warranty so long as a professional chimney technician performs the installation.
The second important aspect is design. Restrictive models will only add to the frustration of weak draft problems and smoking issues. Well-designed chimney are built with air flow in mind, but also to provide a solid defense against most critters.
Spring time brings new life not only to the natural landscape, but also in the form of new broods of raccoons, squirrels, birds, bats, and other adventurous members of the Connecticut wildlife that have an eye for dormant chimneys. In some cases, nests will block the chimney flue and you won't know it until you start that first fire and all the smoke blows back into the house. In other cases, you may be surprised by a scampering family of squirrels leaving a stream of sooty pawprints as they try to find their way out. Most unfortunate critters won't be able to find their way out of the flue and they'll succumb for lack of food and water. No Febreze spray or Glade Aromatic Wicks will eliminate the stench of decomposition coming from the fireplace or flue.
Besides protecting against animal intrusion, the mesh will also serve as a spark arrestor. Some fires have started from flying embers that managed to exit the flue only to land on the roof. A chimney cap's will go a long way in protecting your home.
Didn't expect this topic to be so involved, did you?
Well-designed chimney caps deflect downdrafts, allowing for smoke and fumes to exit the passage without being blocked by cooler air streams that sweep over the roof and into the flue.
And finally, water protection. Water carved the Grand Canyon, so an exposed, aged masonry chimney and clay flue tiles are prone to deteriorate from water damage. In flues venting oil appliances, boilers, water heaters or furnaces, when water mixes with the residue in the chimney flue, the result is sulfuric acid, which will accelerate the deterioration process and pose a real danger in terms of blocking your flue. The acid will eat at the flue lining and cause flakes to accumulate at the bottom. Given enough time, the accumulation may indeed block the fumes from safely exiting your home and leaking back inside.
Although no cap will keep every single water molecule out of the flue, it will undoubtedly prolong the life of your chimney systems.
A chimney cap is only as good as its installation. As mentioned before, only a chimney professional has the training to determine the right cap for your chimney system. The technician will ensure the chimney cap allows for the proper clearances needed to preserve optimum air flow and maximum protection of your system.
If you take into account what it would cost to remove animals, hire a cleaning service to eradicate soot and smoke damage from blocked flues, repair a water-damaged chimney, which may involve relining an entire chimney flue, or heaven forbid, fire damage, a chimney cap is a sound investment no matter which way you look at it.