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Homes that have suffered a chimney fire should be inspected by a chimney sweep, on average there are 25000 chimney fires annually causing 125 million dollars of damage in the United States.
What is a chimney fire?
When you look at your fireplace chimney from the outside of your house, most people only see the aesthetic side of it and not its true function.
Aside from it looking architecturally pleasing it has a much more important function of removing dangerous flue gases from your fireplace or woodstove, keeping your family and home safe, your chimney is also what creates draft and keeps your fire burning properly.
Rarely does anyone sitting in front of their fireplace or woodstove relaxing with a glass of wine ever think about the condition of the inside of their chimney flue. but a chimney fire is something very serious because it is literally a fire that starts inside your chimney and most chimneys are not normally designed to handle something that intense.
Fires happen because of the byproduct of the smoke traveling up your chimney and overtime collecting on the inside of your flue and becoming what is called creosote, a highly flammable tar-like substance.
In this post, I’ll talk about how you can determine if you have had a chimney fire, what damage can it cause to your chimney, and what preventative measures you can take to protect your family and home from ever having a fire
So continue reading and will talk about those 3 important things you need to know about chimney fires.
How can a chimney fire affect your chimney?
Really there are so many ways a fire can affect your flue and it all depends on the type of chimney you have, so let’s start by looking at the differences between them and this way seeing how a fire can affect yours.
Chimney fires in masonry chimneys
If you have a fire in a masonry chimney, the maximum temperature that it can resist is 2000 degrees Fahrenheit, but at that temperature and temperatures lower than that thermal shock occurs causing the clay tile lining to crack, break, and even collapse, and if your chimney is lined with a stainless steel liner, it can melt or be damaged beyond repair and in most many cases need replacing.
On the outside of a masonry, chimney damage can also occur, you can have cracked mortar joints and bricks if you have a severe fire, bricks and mortar may even break away from the chimney, chimney fires also can destroy mortar in the smoke chamber, if the damage from a chimney fire is extensive it can leave wood framing exposed and catch fire to your home, and if the damage is not repaired you could be leaving a crack in your chimney that allow smoke to seep in your second story or attic, becoming a ver dangerous carbon monoxide threat.
Factory-built, zero clearance fireplaces with metal chimneys
This type of fireplace is normally tested at 2100 degrees Fahrenheit in case of a fire and in testing the chimney can resist this temperature, but during a chimney fire the metal can be exposed for a longer time, normally they last much longer than in testing and your chimney can be compromised and may need replacing before further use.
If a metal chimney is exposed to a chimney fire for a long period of time it can melt or buckle causing it to lose its structural integrity, a chimney that is buckled inside should be replaced be for further use.
Buckling can also occur in the firebox and smoke chamber of a factory-built fireplace and this also weakens it and could also need to be replaced.
Black connector pipe on a wood stove
Generally, people that own wood stoves have hot fires in them, and the main function of a wood stove is built to heat up and radiate that heat into your room, but if you have a chimney fire in a wood stove the fire doesn’t normally damage the stove but will damage the black metal connector pipe that connects your stove to your chimney, this pipe can get red hot and melt exposing a chimney fire into your home,
1. What causes a chimney fire?
Simply put chimney fires are caused by dirty chimneys that have lacked maintenance and regular cleanings, it the back wall of your fireplace looks anything like the picture below then you are overdue for a cleaning, and the next picture below that shows the same chimney after being swept.
So later in this post, I’ll talk about the frequency of your cleanings and how you can gauge if it’s time to have your chimney swept.
Creosote is caused by flue gases that travel up your chimney and slowly collect on the inside, if a chimney is not swept before your chimney gets really dirty then the accumulation over time becomes dangerous and can catch fire causing a chimney fire.
Common things that can cause chimney fires
In my time as a chimney sweep I have seen a lot of things that help a chimney fire ignite, but I wanted to mention some of the most common ones I have seen in my career, and the first one is when people want to get rid of an old dried out Christmas tree, so what’s the best way to get rid of it well stuff pieces of it in the fire right? well even though that sounds like a great idea dry pin trees have dry pine needles and when they catch fire they tend to fly up the chimney and cause chimney fires quite frequently.
The second thing that can cause a chimney fire to ignite is wrapping paper from Christmas gifts, yes that’s right your heard me right wrapping paper, what happens is people are opening gifts on Christmas morning with a fire going and the easiest way to get rid of it is burn it so everyone throws the wrappings in the fire, and the paper is so light that is going up the chimney while burning and catches the accumulated creosote on fire, believe me, the last thing anyone wants is a chimney fire Christmas day, but I have seen it a hundred times.
Another thing that can cause a chimney fire is an excess of creosote or garbage above your damper in the smoke chamber, with enough heat from a roaring fire this can ignite and cause a chimney fire,
A birds nest can also be a big problem because they build them in the spring when you stop using your fireplace, and generally, people don’t know they have a nest in their chimney till you start your first fire and it smokes your house out, but sometimes you can not tell if you have a nest because your fire is burning fine, but hot embers in a fireplace or woodstove can go up the chimney and cause the bird’s nest to ignite.
2. What are the signs of a chimney fire?
Chimney fires, for the most part, go undetected and most people that have had one or don’t even know when it happened, chimney fires come in all shapes and sizes and can burn slowly or quickly and they almost always cause some sort of damage.
Here are 12 Common signs you have had a chimney fire
- You might see flames coming out of the top of the chimney
- Pieces of flaming creosote coming out the top of the chimney on to your roof or on the ground
- You will see lots of dense smoke coming out the top of the chimney
- Most chimney fires sound like a train or an airplane is going threw your house scaring most people
- You may feel rumbling or shaking
- Puffy popcorn like pieces of burnt creosote may fall inside the firebox or above the damper
- If you have a clay tile liner you may hear a popping sound because the clay tiles are breaking or cracking.
- Roofing damaged from hot creosote
- Cracks in exterior masonry
- Evidence of smoke escaping through mortar joints of masonry or tile liners
- Discolored and/or distorted rain cap
- Warped metal damper or smoke chamber
3. How to prevent chimney fires before they start
let’s look at our 3rd point with some different ideas that can help you prevent a fire before it happens to give you peace of mind when you use your fireplace or woodstove, It’s important to know that everything is ok and you don’t ever leave anything to chance.
Check your chimney creosote build-up regularly
This is very important because you as a homeowner can gauge how much buildup there is in your chimney just by looking inside with a flashlight, first, take a look at the back wall of the fireplace and see definite build-up than the next step is to look up inside your fireplace and look for build-up on the inside of the flue if you see a quarter of an inch of build-up you are overdue for a cleaning, try having it cleaned when you have one eight of an inch of build-up, that like changing the oil in your car every 3000 miles for preventative measures.
Also by looking at your chimney cap from the ground or if you are handy you can check from the roof and see if the cap has any build-up that looks excessive or if your cap has a wire mesh on it to keep out birds and it’s covered in build-up then its time to have it cleaned.
If you are unsure if it needs cleaning a great idea is to take some pictures and send them to a local chimney sweep so he can give you the proper advice.
Schedule an annual chimney cleaning and inspection
Everyone knows that doing maintenance on a car is so important for it to continue functioning properly and not let us down, well the same thing happens with our chimney it needs regular maintenance, after all the chimney of your fireplace or woodstove is like a motor keeping everything moving and when its clogged up it won’t function right.
If you have your chimney cleaned and inspected at least once a year you should have no trouble with chimney fires as long as you burn well-properly seasoned firewood, if your burn a lot of wood during the year, for example, three cords of wood then you might want to have it cleaned more than once maybe at the beginning of the season before your first use and once again in December or January.
If you live in the United States you can contact a certified chimney sweep and or inspector to take a look at CSIA (Chimney Safety Institute of America)
If you live in Canada you can find certified a chimney sweep and or inspector at W.E.T.T ( Wood Energy Technology Transfer)
Both institutes have properly trained chimney sweeps, inspectors, and installers that are certified and insured.
Install a solid Chimney Cap
Animals can nest in your chimney and as I mentioned before birds are the biggest culprits in doing this although squirrels and chipmunks also like to make their homes in chimneys, and a chimney is a perfect nesting spot, can you blame them for wanting to use it is naturally warm.
Also if you live close to trees or a forest, leaves or pine needles can be a real problem when falling down inside drying out and becoming an excellent firestarter inside your chimney, causing a chimney fire.
Installing a chimney cap is the solution, the cap will keep out almost everything even rain, and protect you from a chimney fire, I recommend buying a stainless steel chimney cap because it will last forever, the one in the picture is one that I personally install and have never had any problems with them, the Stainless steel and Copper makes them look great, and last forever.
Use fire starters that are safe
Don’t ever cut corners with fire starters thinking you can burn almost anything that lights quick, this is a dangerous habit for some, never use gasoline and Kerosene to start a fire these are highly flammable liquids and will burn out of control very quickly so never, never, never use them.
Don’t use too much paper because it can be sucked up a chimney and start a fire, glossy cardboard, and magazines can emit a lot of smoke, also the paper from gift wrappings tends to be very light and will travel right up your chimney possibly causing a fire.
Safe fire starters that work great:
Bangerz Sunz Fire Starter Squares Fire Starters that will get a fire going anywhere fast, these eco-friendly, non-toxic recycled wood chip and wax, emit up to 80% less carbon monoxide.
CHENCY 100% Natural Fire Starter These fire starters are made from mountain pine shavings rolled into small charcoal starters dipped into wax and have no chemical additives they are non-toxic and odorless. with108 pieces in each pack they are a great value for the money.
Duraflame Firestarter Duraflame fire starters are for Indoor and Outdoor. use, they are compact, all you do is light the wrapper and it does the rest, burning up to 30 minutes, they are also water-resistant.
Prevent chimney fires by burning as clean as possible
Burning clean is part of your maintenance too, so let’s look at some different ideas that will prevent a chimney fire and still enjoy your fire.
The first way you can burn a cleaner fire is by seasoning cutting, splitting, and stacking your firewood as soon as you receive it, wood needs to be seasoned for at least 12 months, dry firewood that has no more than 20% moisture content is optimal and you will automatically lower the amount of dangerous creosote build up inside your chimney. For more information on this subject check out my post on HOW TO SEASON FIREWOOD? 7 IMPORTANT THINGS TO KNOW
The second way is to make sure your wood-burning appliance is EPA certified, most modern wood-burning stoves and fireplaces are certified, an EPA Certified product will help reduce the amount of wood needed to heat in your home. Try to avoid wood stoves that are uncertified products as they tend to burn more wood and create significantly more pollution than one that is EPA certified.
My last suggestion is to burn a hot fire that is not dampened down too much, although slowing the airflow allows your wood to burn longer it does create significantly more creosote accumulation in your chimney, try to never allow your fire to smolder overnight.
Does creosote remover really work?
The answer to this question is yes, it really does work. There are many different brands out there some better than others like anything in life but if used properly creosote removers can do two things well.
The first one is if used on a regular basis the creosote in your chimney becomes less flammable over time, but remember it still is flammable but these products definitely make a difference by changing the chemical makeup of the creosote leaving it less flammable.
The second thing it does very well and helps your chimney sweep when he comes for his annual visit to clean your chimney, why is that? well, the creosote that has been treated with creosote remover is much easier to brush and clean because after regular treatments it becomes brittle and flaky falling off easy, and generally more creosote comes off than a normal cleaning without treatment of creosote remover.
Anyone can use these products for peace of mind just remember that they are not an alternative to cleaning your chimney, you still need to get it cleaned every year.
The other type is powder by a company called Rutland and it comes in a container with a small measuring scoop, this type is applied directly to the burning fire then traveling up your chimney it takes effect.
I highly recommend these products to my own clients and anyone that has had problems with creosote glazing or extensive buildup.
Now you have probably seen the chimney sweeping log and are wondering if they work to prevent chimney fires, and the answer again is yes a little bit but you would need to burn a lot of them and you still need to get your chimney cleaned by a professional chimney sweep, the chimney sweeping log does not magically clean your chimney but it does create a similar effect as the creosote removers.
The problem with the chimney sweeping log is 1 of them isn’t enough to affect your chimney, and one bottle of cre-away is like burning a bunch of them in one tiny bottle that you can use over and over again, also you can only burn the chimney sweeping logs in an open fireplace they can’t be used in a woodstove or any airtight stove or appliance, so as you can see there are many more cons than pros to burning chimney sweeping logs.
I really hope you could find value in this post and that you will share it with any friends that have a fireplace or woodstove to keep them and their families safe during the burning season, thank you for taking the time to read, and please take a look at my other posts that have been of great help to others.
Thank you for reading