We’re not really sure if Santa actually slides down chimneys to deliver presents on Christmas. However, we know for sure that chimneys get the smoke out of a house when the fireplace or stove is on.
Still, what goes into the process? How do chimneys work?
Read on to learn more about how chimneys suck the smoke out of houses, the importance of a chimney’s flue, and the liner of a chimney’s flue.
Do all houses have a chimney: can a house not have one?
Most houses have a chimney as people used to burn wood and other items. More recently, the chimneys have been reused for other purposes.
Chimneys are still needed for gas-based water heaters and heating systems. These systems emit dangerous gasses that have to be emitted outside. It is not allowed to install systems that emit this exhaust inside a house.
Chimneys are also needed for houses that are burning wood.
It is essential that the chimney works properly in these cases. A bird can build a nest inside them if you don’t have a chimney cap. Other dirt and dust can also build up inside them. This is why chimneys have to be cleaned often.
Newer homes often have a heat pump. These systems work on air or ground heat. In these instances, the houses don’t need a chimney as there is no exhaust that has to be emitted. We can expect that chimneys will become less needed in the future.
While chimneys are very handy, they also bring cold air inside a house. This can increase the energy that is needed to heat up a house.
Chimneys are sometimes also used for kitchen range hoods. These bring the dirty air outside. There are systems that are filtering the air inside the house as well and you don’t need a chimney if you have one of these.
Are chimneys load bearing: how to break them down?
Chimneys are an essential component of a home for proper ventilation. It allows the hot air produced by your stove, gas water heater or gas heating system or fireplace to exit your home.
The way chimneys work is predicated on simple physics. Specifically, it revolves around the fact that hot air always rises above colder air.
When your stove or fireplace is ablaze, the flame releases hot gases such as carbon dioxide. These gases have a higher pressure than the cooler gas inhabiting your chimney.
The hot gases want to expand into areas of lower pressure. This makes them fill up your chimney, moving upwards and pushing the cooler gas downwards.
This cycle continues until the air pressure in your chimney is equal to the air pressure inside your house. In other words, this cycle goes on until you’ve turned off the heat source and the conditions in your home have returned to their initial state.
This flow of air created by your chimney is referred to as a draught. The hotter the temperature reached by your fireplace or stove, the stronger the draught.
You should also note that extracting smoke and hot gases from your house isn’t a chimney’s only job. The cool air that’s pushed out of the chimney into your house helps keep your fireplace’s flame going by providing it with the oxygen it needs.
Chimneys might be load bearing or structural. You will have to check with a structural engineer to make sure that you can remove it without damaging your house! Chimneys run across your house and carry parts of the load so be careful when you are working around it!
Once you are sure that they are not load bearing, you can use power tools such as a chipping hammer. Chimneys can collapse at any point so you have to be careful when you do this! Also check if there is metal in the concrete before you start. Wear gloves, goggles and strong shoes and other protection when you work on this!
What is a Chimney Flue pipe and does it have to be straight?
Contrary to what some may think, a chimney isn’t simply a hollow rectangular brick structure. One of the most critical components of a chimney is its flue.
A chimney’s flue is the lined passage that starts from right above the fireplace and extends all the way up a chimney’s interior. The lining of the flue is absolutely essential to the health of a chimney and, in turn, the safety of the household.
When it comes to containing hot gases, brick isn’t a reliable material. Smoke and hot gases can seep sideways through the bricks instead of moving upwards through the chimney. This is incredibly dangerous because it’s a chimney fire waiting to happen.
The flue lining is typically a solid structure with no spaces in it. This significantly reduces the chance of any smoke getting by. However, the flue lining isn’t 100% foolproof and can deteriorate over time.
Therefore, you must check up on your chimney’s flue lining regularly.
You should also note that one chimney may have several flues. This is usually the case when several appliances emit smoke and hot gases that need to be expelled from the house.
In other words, the more smoke emission you have, the more likely you’ll need another flue layer.
Chimney flues often have a bent. Check your local code to see what is allowed as each location is unique in this perspective. It is essential that the smoke can go outside without creating condensation inside the flue pipe.
Do roofers do chimneys?
While plumbers might do some work on a chimney, in most instances they will call a roofer for help. Roofers have to know how to use a lot of materials as chimneys are made out of metal lining and bricks.
Flue lining is crafted from various materials, each with its own benefits. The best flue lining for you largely depends on the type of fuel you use in your fireplace.
Here are the main types of flue lining.
Metal Lining
Some flue linings are made of metal. The types of metal commonly used are aluminum and stainless steel.
Installing metal flue lining is a great option when repairing or renovating your chimney. Metal lining offers peak safety from chimney fires and is incredibly long-lasting. But, of course, this is under the condition that you carry out regular check-ups and maintenance.
Whether you should go for stainless steel or aluminum depends on the fuel your appliances depend on. For example, stainless steel is the better option if your fireplace or stove is gas, oil, or wood powered.
The only major drawback of metal flue lining is that it’ll have you digging deeper into your pockets than the other lining material options.
Clay Tile Lining
Clay tile lining is the one traditionally used for flues and is also the most cost-effective.
However, clay tile lining has become rather outdated in this day and age for a couple of reasons.
Even if you do the required maintenance and check-ups, clay is simply not as effective as metal in preventing chimney fires. It also doesn’t hold up well at all if a chimney fire is already raging.
The structural integrity of clay is severely compromised when a sudden rise in temperature occurs. Additionally, the clay lining is susceptible to cracking, rendering it useless in protecting your household from the toxic, flammable gases that your fireplace emits.
Also, clay lining isn’t designed to handle the emissions of newer gas-powered stoves and fireplaces.
Cast In Place Lining
Cast-in-place lining is cement based. It provides your flue with an excellently insulated, solid shield to keep smoke and hot gases moving upwards through your chimney as opposed to outwards.
This type of lining is often used to shore up the lining of older chimneys. It’s also highly versatile and can handle the fumes that are produced by all types of fuel combustion.
Can a house not have a chimney: do all houses have one?
Conclusion
Although chimneys are considered synonymous with older houses, these structures are more complex than you’d think.
If you were wondering, how do chimneys work? Here’s the answer.
Chimneys depend on the fact that hot air rises above cooler air due to the difference in pressure between them. This creates an upwards air flow referred to as a draught.
The draught created by your chimney pushes the hot gases emitted by your fireplace through your chimney and outside your house.
In order to ensure maximum safety from chimney fires, you should always check up on your chimney regularly and ensure that the flue lining is in good shape.
Getting your chimney inspected and cleaned often is essential.
