Chimneys, fireplaces, and vents shall be inspected at least once a year for soundness, freedom from deposits, and correct clearances. Cleaning, maintenance, and repairs shall be done if necessary. This is the national safety standard and is the correct way to approach the problem. It takes into account the fact that even if you don’t use your chimney much, animals may build nests in the flue or there may be other types of deterioration that could make the chimney unsafe to use.

The Chimney Safety Institute of America recommends that open masonry fireplaces should be cleaned at 1/4″ of sooty buildup, and sooner if there is any glaze present in the system. Factory-built fireplaces should be cleaned when any appreciable buildup occurs. This is considered to be enough fuel buildup to cause a chimney fire capable of damaging the chimney or spreading to the home.

Firewood is an area where you can have great influence over how well your system performs and how enjoyable your experience will be. Quality, well seasoned firewood will help your wood stove or fireplace burn cleaner and more efficiently, while green or wet wood can cause smoking problems, odor problems, rapid creosote buildup and possibly even dangerous chimney fires.

A few minutes spent understanding firewood will be time well spent, so please read on for general background information, as well as how to buy wood and store wood.

Seasoned Wood

All firewood contains water. Freshly cut wood can be up to 45% water!, while well seasoned firewood generally has a 20-25% moisture content. Well seasoned firewood is easier to start, produces more heat, and burns cleaner. The important thing to remember is that the water must be gone before the wood will burn. If your wood is cut 6 months to a year in advance and properly stored, the sun and wind will do the job for free. If you try to burn green wood, the heat produced by combustion must dry the wood before it will burn, using up a large percentage of the available energy in the process. This results in less heat delivered to your home, and literally gallons of acidic water in the form of creosote deposited in your chimney.

Wood is composed of bundles of microscopic tubes that were used to transport water from the roots of the tree to the leaves. These tubes will stay full of water for years even after a tree is dead. This is why it is so important to have your firewood cut to length for 6 months or more before you burn it, it gives this water a chance to evaporate since the tube ends are finally open and the water only has to migrate a foot or two to escape. Splitting the wood helps too by exposing more surface area to the sun and wind, but cutting the wood to shorter lengths is of primary importance.

There are a few things you can look for to see if the wood you intend to purchase is seasoned or not. Well seasoned firewood generally has darkened ends with cracks or splits visible, it is relatively lightweight, and makes a clear “clunk” when two pieces are beat together. Green wood on the other hand is very heavy, the ends look fresher, and it tends to make a dull “thud” when struck. These clues can fool you however, and by far the best way to be sure you have good wood when you need it is to buy your wood the spring before you intend to burn it and store it properly.

Storing Firewood

Even well seasoned firewood can be ruined by bad storage. Exposed to constant rain or covered in snow, wood will reabsorb large amounts of water, making it unfit to burn and causing it to rot before it can be used. Wood should be stored off the ground if possible and protected from excess moisture when weather threatens.

The ideal situation is a wood shed, where there is a roof but open or loose sides for plenty of air circulation to promote drying. Next best would be to keep the wood pile in a sunny location and cover it on rainy or snowy days, being sure to remove the covering during fair weather to allow air movement and to avoid trapping ground moisture under the covering. Also don’t forget that your woodpile also looks like heaven to termites, so it’s best to only keep a week or so worth of wood near the house in easy reach. With proper storage you can turn even the greenest wood into great firewood in 6 months or a year, and it can be expected to last 3 or 4 years if necessary.

Buying Firewood

Firewood is generally sold by volume, the most common measure being the cord. Other terms often employed are face cord, rick, or often just a truckload. A standard cord of firewood is 128 cubic feet of wood, generally measured as a pile 8 feet long by 4 feet tall by 4 feet deep. A face cord is also 8 feet long by 4 feet tall, but it is only as deep as the wood is cut, so a face cord of 16″ wood actually is only 1/3 of a cord, 24″ wood yields 1/2 of a cord, and so on.

Webster defines a rick simply as a pile, and truck sizes obviously vary tremendously, so it is very important that you get all of this straight with the seller before agreeing on a price; there is much room for misunderstanding. It is best to have your wood storage area set up in standard 4 or 8 foot increments, pay the wood seller the extra few dollars often charged to stack the wood, and warn him before he arrives that you will cheerfully pay only when the wood actually measures up to an agreed upon amount.

Another thought concerning getting what you pay for is that although firewood is usually sold by volume, heat production is dependent on weight. Pound for pound, all wood has approximately the same BTU content, but a cord of seasoned hardwood weighs about twice as much as the same volume of softwood, and consequently contains almost twice as much potential heat. If the wood you are buying is not all hardwood, consider offering a little less in payment.

The smell is due to creosote deposits in the chimney, a natural byproduct of woodburning. The odor is usually worse in the summer when the humidity is high and the air conditioner is turned on. A good cleaning will help but usually won’t solve the problem completely. There are commercial chimney deodorants that work pretty well, and many people have good results with baking soda or even kitty litter set in the fireplace. The real problem is the air being drawn down the chimney, a symptom of overall pressure problems in the house. Some make-up air should be introduced somewhere else in the house. A tight sealing, top mounted damper will also reduce this air flow coming down the chimney.

This has become quite a common problem in modern air tight houses where weather-proofing has sealed up the usual air infiltration routes. The fireplace in use exhausts household air until a negative pressure situation exists. If the house is fairly tight, the simplest route for makeup air to enter the structure is often the unused fireplace chimney. As air is drawn down this unused flue, it picks up smoke that is exiting nearby from the fireplace in use and delivers the smoke to the living area. The best solution is to provide makeup air to the house so the negative pressure problem no longer exists, thus eliminating not only the smoke problem, but also the potential for carbon monoxide to be drawn back down the furnace chimney. A secondary solution is to install a top mount damper on the fireplace that is used the least.

Without a doubt! Although gas is generally a clean burning fuel, the chimney can become non-functional from bird nests or other debris blocking the flue. Modern furnaces can also cause many problems with the average flues intended to vent the older generation of furnaces. We suggest you check the areas on gas and carbon monoxide for more information.

“I have an 80 year old home that was a longtime rental house. I have lived here five years and have been using the fireplace for four of those years. I do not know how long it has been since my chimney was swept (potentially decades, if ever). I just had a chimney sweep at my house and he informed me that the creosote in my chimney was quite thick (he used the term “level 3″ creosote). He also said that in the smoke chamber, the brick is stepped (instead of smooth) and that there is a lot of dangerous buildup in there. He recommended two applications of an acid cleaning (which he said are not entirely foolproof, and work better above 45°F) and that we use a chemical when we burn our fire to help “chalkify” the creosote buildup. He showed me the buildup inside with a light and everything he said seemed to make sense. Does this sound like it’s on the up and up? I can’t find any info on this acid cleaning and I would like to know if this sounds like it is the proper course of action in a case like mine.”

What you have described sounds pretty typical. In addition to the chemical treatment that you mentioned, professional-grade chemicals, usually in the form of a powder, can be applied by chimney sweeps to help change the nature of the glazed creosote to a form that can be removed by a professional with a brush Both forms of these products require some heat such as you would find in a small fire in the fireplace.

If the creosote is gummy, about the only way to deal with the creosote is with a chemical treatment or with an acid application. Acid applications are not as commonly used since they are harder to apply and have to be neutralized a few days after application. If the creosote is crusty or fractures when hit (as opposed to gummy) a rotary cleaning can be helpful. Read our position statement on chemical chimney cleaning products here.

“In the past, sweeps we’ve hired have always gone on the roof, checked the flashing, the mortar and all the workings of the chimney and then cleaned the chimney from the top of the house. Today, this sweep came in, looked into my fireplace from the bottom and said we don’t need it clean because he can still see the bricks. My asked to have it cleaned anyway. He then grabbed a wire brush and simply rubbed away any buildup from the main opening to the fireplace without even going up into the chimney to clean anything. Am I way off base, or did the sweep charge me without cleaning my chimney?”

Your past experiences with chimney sweeps sound as though the sweep did the job he was hired to do. However, your most recent experience sounds a bit odd. If the sweep agreed to do a complete sweeping and only cleaned the brick in the fireplace firebox, you did not get the service that you paid for. A complete chimney sweeping includes the chimney flue and smoke chamber.

In the future you could ask for a Level 1 chimney inspection and a chimney sweeping. If the sweep doesn’t know what a Level 1 inspection is, find one that does. A Level 1 inspection is detailed in the National Fire Protection Association 211: Standard on Chimneys, Fireplaces, Vents and Solid Fuel-Burning Appliances.

“Is there some standard building requirement for the flue and the fireplace that you can’t just look up from the fireplace and see the sky or chimney cap at the top of the chimney?”

Flues are allowed to have up to 30 degree offsets. In most cases this will make a direct visual observation of the flue impossible. A video scan would be required to evaluate the flue condition.

The height of the chimney flue is not a factor. There is a big difference in what is observed between a visual inspection and a video inspection, even in short flues.

To protect your home from water damage caused by rain. One main reason for the breakdown of fireplaces and chimneys is water. Chimney caps also keep birds, squirrels, and other critters from nesting in your home.

If your chimney is not properly sealed, it’s like leaving your front door open all year long! That could be $350 – $500 going up your chimney every year in additional energy costs.

When there’s a crack bigger than a dime.

All chimneys should be checked and cleaned to insure all deposits and obstructions are removed.

When the logs become black with carbon deposits and/or the pilot light continues to go out.

Unfortunately, there is no such thing as creosote-free wood burning. Creosote accumulation will occur no matter what kind of wood is burned and no matter what kind of wood burning system is used. What determines the type of creosote and its severity is how the fuel is burned. Solid fuel authorities agree that the amount of smoke, the temperature of the fire and the regulation of air (turbulence) are the major variables which determine the amount of buildup. A low burning fire, for example, will result in incomplete combustion, the number one cause of glazed creosote accumulation. An improperly installed fireplace insert, one that allows the smoke to cool too quickly in the firebox, is another situation which causes severe glazing. To combat this problem, flue gases should be kept between 250 degrees and 500 degrees F. if creosote accumulations are to be reduced in amounts and in thickness. (Be sure to ask your chimney sweep about proven methods to assure correct burning.) If your chimney sweep has already diagnosed glazed creosote as a problem in your chimney take his or her advice seriously. DO NOT continue to use your affected fireplace or wood stove. The simple fact is that a hot fire could easily ignite the glazed creosote and result in a dangerous chimney fire. And a low burning fire under such hazardous conditions will only worsen the glazed creosote problem.