Chimney 101: Why Your House Has One Of Those

When you look at your roof, you may see some open pipes sticking out of it. What are these pipes and why are they there? Some people call these chimneys, but it would be more technically correct to call them vents or exhausts. In general, there are three types of "chimneys" that you can have on your roof.

Brick and Mortar Chimneys

The first is the standard chimney that goes to your fireplace. They are usually made of brick, stone, or some other fire-resistant material. Its purpose of course, is to give the smoke from the fire somewhere to go. However, this chimney is much more than just a simple tunnel to the outside. There is a part in the chimney that actively works to keep carbon dioxide from coming out of the fireplace. The flue controls the amount of oxygen that comes into the fireplace from its surroundings. This can create a large crackling fire, or damp it down to a few pleasant flames and coals.

Exhausted But Working

An exhaust vent attaches to your gas fired furnace or water heater. Its purpose is the same as a normal chimney. It prevents the buildup of combustion byproducts in your home. Without the exhaust, carbon dioxide would settle in your basement and eventually seep into the living sections of your home. The exhaust for your furnace should be inspected at least once per year to ensure that it is working properly. This inspection usually happens in the spring at the same time you have your furnace inspected.

In and Out

The third type of chimney is actually a vent that draws air in as well as acting as an exhaust. The vent is an essential part of your plumbing. It allows air to enter into your drainpipes so the waste and water can flow out without any problems. The air cannot come from the drains themselves because all of the drains (sinks, showers) have a u-bend in them. This u-bend fills with water and prevents air from flowing in either direction. You want this water there because otherwise sewer gases could flow back into your kitchen or bathroom. Instead, the vent in your roof allows the influx of air to let the water drain and provides an escape for the noxious gases.

The next time you see all of the pipes sticking out of your roof, you will not have to wonder what they are and what they do. If your chimney needs to be repaired, contact Steve's Masonry Service or a similar company.

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