How to Prevent Soot Buildup in Wood Stoves

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Wood stoves are popular in both modern homes and traditional homes because of how easy they are to operate.
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Wood stoves are popular in both modern homes and traditional homes because of how easy they are to operate, but the adversary you'll deal with is tar in wood-burning stoves. There is a broad selection of wood stoves that will provide what you're looking for, and they do an amazing job at heating the home. You just want to make sure that they don't build up soot and you're always keeping them clean.


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Operation and Wood Combustion

Before you even think of cleaning tar in wood-burning stoves, you need to know how your stove operates. According to the Department of Agricultural Engineering at the University of Missouri, combustion in a wood stove is a chemical reaction between the fuel, in this case wood, and oxygen. If there is combustion of wood in the stove, then you'll get heat and water vapors, carbon dioxide, gases and ash. There are a couple of conditions you need to meet to operate a safe wood stove.


First, make sure there is a continuous airflow or supply of oxygen for the fire and people that are around the wood-burning stove. Next, you need to make sure there is a proper amount of fuel, in this case wood, to make sure that the wood stove isn't overheating. You want to make sure there is enough wood, though, to maintain the flue temperature so there isn't an accumulation of creosote residue. The flue is a duct for smoke and waste gases. Always make sure that you're burning correctly so there isn't wasted fuel or a buildup of toxic products.


Stages of Wood Combustion

According to the Department of Agricultural Engineering at the University of Missouri, there are three basic stages of wood combustion. The first is that water will be removed by evaporation and vaporization. This type of heat, though, will not warm the room or stove.


During the second stage at 500 F, the temperature will cause the wood to break down chemically, and volatile gases will form. The vapors contain about 50 to 60 percent of the heat value of wood. At around 1,100 F, the gases will mix with air, become flames and burn. You have to maintain this temperature and the right amount of air supply to support proper combustion.


In the last stage, the gases release. When this happens, the remaining material, which is charcoal, will burn at an excess of 1,100 F. When the charcoal is completely burned, a bit of ash will remain.

Read more: How Hot Can Wood Stoves Get?


Tar in Wood-Burning Stoves

When wood burns slowly in a wood-burning stove, the smoke contains something called creosote. Creosote is a brownish, oily liquid that has aromatic hydrocarbons obtained by the distillation of coal tar, and it is used as a wood preservative. The dark brown or black flammable tar is deposited from the wood smoke on the walls of the chimney.


According to the National Fire Protection Association (NFPA), creosote is highly flammable, and if the buildup is not removed, then this can cause a deadly chimney fire. The main reason for creosote buildup or tar in wood-burning stoves is that there is wet or unseasoned wood, incomplete combustion is occurring or the surface is cooler than usual.


Stages of Creosote

According to the NFPA, there are three stages of creosote, and as the stages increase, the more hazardous and difficult it is to remove. That means that you should try and remove creosote as soon as possible. The first stage of creosote is when it looks more like flaky soot. At this stage, it is very easy to brush away the creosote with a chimney brush.

In the second stage, the creosote looks shinier and has hard, black flakes. The flakes are hardened tar, and this tar can't just be brushed away. To remove the tar, you're going to need a rotary loop. This is a powerful drill that turns metal rods.

The final stage is a stage that you should never reach. If the creosote gets to this stage, it is complicated to clean, and there is a highly concentrated amount of fuel in your chimney. The fuel looks like a coat of tar, and it drips down the chimney liner. The glazed creosote will drip down, become thick and hard and will layer. If your chimney gets super hot, it can easily ignite this thick tar and becomes extremely hazardous.

Stage Three Creosote Risk

If stage three creosote catches fire, the spongy residue can be easily removed, but you don't want to chance a chimney fire turning into a house fire because of tar dripping from the chimney. If your chimney does become coated with stage three creosote, then it's best that you replace the chimney liner. You can use the rotary head to remove the hardened tar, but it can cause broken chimney tiles, which you don't want to risk.

Read more: Signs & Symptoms of Creosote Damage

Inspections and Cleaning

The best way to control creosote is to prevent buildup by maintaining a briskly burning fire with dry, well-seasoned wood. You also need to keep the flue temperature over 250 F to avoid creosote condensation. Newer stoves deliver more heat to the room than the open stove or fireplace, which means it will reduce the amount of heat going up the chimney. According to MF Fire, it's important to make sure that there isn't a buildup of soot on the wood stove glass.

There's always going to be some form of soot on the wood stove glass if you're consistently using your wood stove. You want to make sure there isn't any buildup. To prevent any excessive buildup, always burn seasoned, nonresinous hardwoods and avoid smoldering fires. According to MF Fire, resinous or wet wood produces oils and compounds that will build upon your wood stove's glass. As far as smoldering fires, new EPA certified stoves can burn for long hours on a low setting. This may seem beneficial for us, but smoldering fires produce more smoke, which will deposit on the glass.

Removing Soot on Glass

If the glass on the stove does get soot on it, it's an easy fix to rectify. According to MF Fire, you can use a high-temperature fire, a wet rag, newspaper and ash or a wood stove glass cleaner to get rid of the soot. When using fire, all you have to do is burn a high-temperature fire in your stove. This is going to be the easiest and go-to method. When the stove cools, it will be easier to clean the glass.

When the wood stove is cooled down, use a wet rag or paper towel to wipe off the lighter haze. If you have stubborn stains that won't go away, use a damp piece of newspaper and dip it into the ash from your stove. Scrub the glass gently to remove the soot buildup. If you really can't get your glass clean, use a wood stove glass cleaner. All you have to do is apply the glass cleaner to a rag and wipe the dirt off.

Read more: 9 Wood Stove Fireplaces That Are Stoking Our Flames