Frequently Asked Questions
- Why do I need help from a knowledgeable hearth professional?
You're choosing an appliance that can bring years of warmth and comfort to your home... if it's installed properly.
Harnessing the beauty and warmth of fire for the home is not a do-it-yourself project or something you should necessarily trust to the lowest bidder. The hearth in any home is a focal point and center for family enjoyment. As such, it calls for important decisions about the appropriate appliance or products for your goals. Proper placement, venting and protection from combustibles are very important considerations. Both for safety and performance, hearth products require considerable technical knowledge and skill in the designing and installation of them.
- How often should my chimney be cleaned or inspected?
Storks nesting in chimneys were once believed to bring good luck, according to European folklore. But, in fact, nests in chimneys - or blockages of any kind - are nothing short of bad news. They can cause smoking problems, chimney fires and carbon monoxide poisoning.
In 1998, there were 18,300 residential fires in the United States originating in chimneys, fireplaces and solid fuel appliances, according to the United States Consumer Product Safety Commission. These fires resulted in 160 personal injuries, 40 deaths and $158.2 million in property damage.
Virtually all of these fires were preventable according to the Chimney Safety Institute of America (CSIA), a non-profit institution dedicated to public and chimney professional education. Both CSIA and the National Fire Protection Association recommend yearly chimney inspections to help prevent these hazards.
Many American homeowners think their chimneys only need to be cleaned and inspected if they burn wood in their fireplaces or wood stoves. But almost all heating appliances, whether they burn gas, oil, wood or coal, rely on the chimney to safely carry toxic gases produced by the heating system of the house.
A carbon monoxide detector can warn homeowners of potential poisoning after the deadly gas has already entered the living area, but an annual chimney check can help prevent carbon monoxide from entering the home in the first place.
Each fall, homeowners shift into home-improvement mode. They clean gutters, garages and basements -- preparing homes for winter. But they usually don't inspect, repair or clean their chimneys, despite the potential for damage to their property or even to their lives.
An annual chimney inspection by a CSIA Certified Chimney Sweep® is a modest investment that can reduce the danger of chimney fires or carbon monoxide poisoning. CSIA Certified Chimney Sweeps have earned the industry's most respected credential by passing an intensive examination based on fire codes, clearances and standards for the construction and maintenance of chimneys and venting systems.
In fact, when chimney fires occur, many insurance investigators rely on CSIA Certified Chimney Sweeps to determine whether a fire originated in - or damaged - the chimney system. The CSIA, established in 1983, is a non-profit, educational institution, dedicated to educating the public about the prevention of chimney safety hazards.
- Why do I need a chimney liner?
A flue lining in a masonry chimney is defined as "A clay, ceramic, or metal conduit installed inside of a chimney, intended to contain the combustion products, direct them to the outside atmosphere, and protect the chimney walls from heat and corrosion." Although building codes vary from one state or locality to another, the installation of flue lining has been recommended since the early part of this century, and indeed most fire codes now mandate liners.
In the 1940's and again in the 1980's, masonry chimneys were tested by the National Bureau or Standards for durability due to rising concerns about their performance and safety. The tests revealed that unlined chimneys were so unsafe that researchers characterized building a chimney without a liner as "little less than criminal".
Liners in chimneys serve three main functions:
1) The liner protects the house from heat transfer to combustibles. In the NBS tests, unlined chimneys allowed heat to move through the chimney so rapidly that the adjacent woodwork caught fire in only 3 1/2 hours.
2) Liners protect the masonry from the corrosive byproducts of combustion. In the tests it was determined that if the flue gases were allowed to penetrate to the brick and mortar, the result would be a reduction in the usable life of the chimney. The flue gases are acidic in nature and literally eat away at the mortar joints from inside the chimney. As the mortar joints erode, heat transfers more rapidly to the nearby combustibles and dangerous gases such as carbon monoxide can leak into the living areas of the home.
3) Liners provide a correctly sized flue for optimum efficiency of appliances. Modern wood stoves and gas or oil furnaces require a correctly sized flue to perform properly. The chimney is responsible for not only allowing the products of combustion a passage out of the house, but the draft generated by the chimney also supplies the combustion air to the appliance. An incorrectly sized liner can lead to excessive creosote buildup in woodburning stoves, and the production of carbon monoxide with conventional fuels.
Types of chimney liners
Chimney liners come in three main types: Clay Tiles, Metal, and Cast-in-place
1) Clay tiles are the most common type of masonry chimney liners. They are inexpensive, readily available, and perform quite well for open fireplace chimneys that are properly maintained. There are two disadvantages to clay tiles. The first is that, being a ceramic product, they cannot rapidly absorb and evenly distribute heat during the rapid temperature rise that occurs during a chimney fire. This uneven heating produces an unequal expansion which in turn causes the flue tiles to crack and split apart. This is similar to immersing a cold drinking glass in very hot water. It will instantly shatter. A chimney with cracked chimney liners must be repaired before use. The second disadvantage is that tiles cannot adequately contain the liquid combustion byproducts produced by modern gas appliances.
2) Metal chimney liners, usually of stainless steel or aluminum, are primarily used to upgrade and repair existing chimneys. These liner systems are U.L. tested and listed, and if properly installed and maintained are extremely safe and durable. Stainless steel is suitable for woodburning, gas, or oil applications, while the aluminum is an inexpensive alternative for certain medium efficiency gas applications only. It is usually required that high temperature insulation be used in conjunction with the liners for safety and performance considerations.
3) Cast-in-place chimney liners are lightweight, castable, cement like products that are installed inside
the chimney forming a smooth, seamless, insulated passageway for the flue gasses. They can improve the structural integrity of aging chimneys, and are permanent liners suitable for all fuels.
Considering the dangers of old unlined or damaged chimneys, and the many cost effective options now available to make these chimneys safe components of the home heating system, may we suggest you have your chimney professionally inspected to be sure it meets modern safety standards.
- Why doesnt my fireplace work properly?
Why fireplaces work, and how best to build them, has been a topic of hot debate literally for centuries. From the first stone rings stacked around the campfire, to the modern factory built fireplaces with carefully engineered dimensions, there has been a steady evolution of design parameters to make sure they draw well and cast as much heat as possible. Most of this evolution has been by trial and error, and some designs work much better than others.
Simply put, fireplaces work mainly because hot air rises. When you start a fire, the air inside the chimney becomes warmer and less dense than the air outside the chimney, and consequently it starts to rise. As the warm air rises, cooler air from the room flows into the firebox, fanning the fire, creating more heat in an ongoing cycle. There are also some pressure differentials produced as wind moves across the top of your chimney.
There must be at least 100 reasons why your fireplace may not function properly. We will try to cover some of the basics here starting with the easy obvious solutions and working towards the more arcane. Please bear in mind this is a very simplified list of the more common reasons that fireplaces don't work A true understanding of fireplaces requires extensive knowledge of air flow patterns, pressure differentials, and actual fireplace construction techniques. If the information provided here does not help you solve the problem with your fireplace, consider hiring an experienced, certified chimney sweep in your area. Often the problem is obvious to someone with enough experience once they can acutally look over the entire situation.
1) Is your damper fully open? Everybody eventually forgets to open the damper. Many dampers also cease to fully open because of water damage or soot buildup behind them on the smoke shelf. A good professional cleaning can usually solve this problem.
2) Is your firewood green or wet from rain or snow? Remember the main reason your fireplace works at all is the heat inside the chimney. If your wood is not dry and well seasoned it makes more smoke than heat and there simply may not be enough heat for the chimney to work properly.
3) Is your chimney dirty? The gradual accumulation of soot can seriously affect the way your chimney performs. Thick layers of soot of course can physically restrict the flue so there is no longer enough free area to vent the fireplace properly, (see problem 5) but as little as a 1/4" to 1/2" inch buildup can make more difference than you might think. Consider that a 1/2" buildup will restrict the air flow by 17% for a typical masonry fireplace chimney, and by a whopping 30% for the average prefab. Birds and small animals also think your chimney looks like a hollow tree in which to set up housekeeping. Sweeps often find chimneys literally packed full of leaves, twigs and baby animals. The solution of course is a good cleaning and a chimney cap.
4) Is your chimney tall enough? To function properly, the chimney should be at least 10 or 12 feet in overall height. Where it projects above the roof, the chimney should be at least 3 feet tall, and at least 2 feet higher than anything within 10 feet of it-including other buildings, trees, etc. If your fireplace smokes because your chimney is too short, the problem is usually worse when the wind blows.
5) Is your flue large enough for the fireplace opening? There are many variables that can affect this including; overall chimney height, how warm the flue stays, throat configuration, etc., but the basic rule of thumb here is that the area of the fireplace opening can be no more than 10 times the area of the flue (12 times for round flues). An undersized flue simply can't handle the volume of smoke produced, and some of it will spill back into the room. Since there is no practical way to make the flue size larger, the solution may be to make the room opening smaller with metal smoke guards or some creative masonry work. In fact there are now some premanfactured refractory firebox retrofits that work well with a 15 to 1 ratio and deliver twice the heat of conventional fireboxes.
6) Is your chimney on the outside of the house? Remember that warm rising air is the basic engine involved here. If you have a large masonry chimney on the outside of the house, and it's cold outside, the air inside of the chimney will also be very cold, and it will want to fall down the chimney instead of rising. This can even happen a day or two after it's warmed up outside. These chimneys may be hard to start and they may smoke as the fire burns low. To help get the fire started many people light some rolled up newspaper and hold it up near the damper to get that cold plug moving upwards. Keeping a moderate sized but bright, actively flaming fire can also help this situation. Remember that as the fire dies down, it will revert back to the original direction of flow.
7) Is your home too tight? Fireplaces require large volumes of air to burn. Visualize a 12" x 12" column of air rising up your chimney and exiting the top the entire time your fireplace is working (but don't visualize your heat bill!). This air comes from inside the living area and must somehow be replaced. With modern energy efficiency concerns most houses have been carefully insulated and weather-stripped to keep out the cold drafts, but an undesirable side effect is that there is often nowhere for all that air leaving the chimney to get back in. This can lead to fireplaces that burn sluggishly and smoke. A temporary solution is to open a window to let in a little make up air, preferably on the windward side of the house. It can also lead to very dangerous carbon monoxide buildup if your fireplace and furnace must compete for combustion air, and a permanent solution should be found at once.
8) Your house can also be too loose! A house that leaks too much air to the outside, especially a multistory house that leaks air in the upper levels, can actually set up its own draft or chimney effect strong enough to overpower your fireplace chimney, particularly if the fireplace is located in the basement on a cold exterior wall. Be sure the attic access door is in place and that all upstairs windows are tightly closed.
9) Is there a return air grill in the same room as the fireplace? As the fireplace consumes air and cold air moves into the house to replace it, the furnace is likely to come on. When the furnace comes on, air is drawn into the return competing directly with the needs of the fireplace.
10) The other 91 reasons your fireplace can smoke have to do mainly with design problems when the fireplace was built. Aside from the chimney being too short, or too small, the chimney can also be too large, too tall, too crooked, etc. ad infinitum! Most of these details are fairly technical in nature, and again a good sweep may be your best bet.
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