Fireplace chimneys

The main purpose of a fireplace chimney is to vent into the atmosphere, hazardous and noxious gases produced by the combustion of burning wood. Also fireplace chimneys help to regulate the right amount of air into the fireplace and help prevent the fireplace from becoming too hot by dissipating heat into the air.

Before the availability of different types of metals, fireplace chimneys were constructed out of brick and mortar and lined with fireproof tiles. The newer models are much easier to install and build compared to the older days.  Not only must a fireplace chimney be able to withstand high temperatures, but also the corrosive compounds produced by the combustion process.

The Flue, which is the space inside the chimney often forms a flammable substance called creosote. This substance is hazardous because it can block the flow of air through the chimney and can block burning materials. It’s important to perform proper maintenance on your chimney to prevent creosote buildup over time.  Some good characteristics of a properly designed chimney include: Easy lit fires and a draft that builds quickly, no smoke spills into the room when you open the door to take care of the fire, smoke doesn’t fill up the room when lighting a fire, and no bad odors or cold air coming in from the hearth area when the fireplace isn’t in use. A good chimney will also produce a greater draft which will prevent smoke from pouring into your home and cause the fire to burn brightly and for a long time in your fireplace. 

There are three main accessories that are designed to be used with chimneys. Chimney caps, chimney surrounds and dampers. A chimney cap is positioned on top of the chimney for the purpose of improving the chimney draft and to keep birds and squirrels from making nests inside the chimney. Often a wire mesh is placed on top of the chimney underneath or in the cap to prevent sparks from making it onto the roof. A chimney surround or cowl is essentially the same thing as a cap, but is enclosed and will rotate with the wind to prevent smoke and wind from going back into the chimney. A fireplace damper is used to insulate your home from the open air. Make sure you close your fireplace damper when the fireplace is not in use, because it’s the same as leaving a window open in your home. You can also use tight-fitting glass doors to keep the outside air from coming into your home