Please Note: Wood and Gas CANNOT be vented out of the same flue or liner. Wood burning liners cannot be used with gas appliances and vice versa. If you want to convert from one fuel to another, the liners MUST also be changed to conform to code.
What is the Purpose of a Chimney Liner?
• Contains combustion products.
• Directs the combustion products to the outside atmosphere to keep them from entering your home and causing poisoning or death.
• Protects the chimney walls from heat and deterioration.
Reasons To Reline:
• Addresses incorrect chimney construction.
• Corrects safety issues by nature (Cracked flue tiles, shifting, loose or missing mortar joints)
• If a chimney is unlined.
• Prevent a transfer of extreme heat to combustible materials to prevent fires or pyrolysis.
• Prevents the flue gases to attack masonry structure and shorten it’s life.
• Prevents carbon monoxide or smoke to leak into the home.
• Prevents possible liner leaks to the combustibles.
• If there are missing or misaligned flue tiles
• If there are missing mortar joints (Dry Stacked)
Chimney Relining corrects safety issues created by:
• Earthquakes, settling
• Water damage.
• System deterioration caused by acid and flue gases.
How common is it that chimney liners cannot be seen from inside the fireplace using only a flashlight? 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.
What stainless steel liners require insulation?
Liners for gas and oil-fired appliances do not require insulation to meet the manufacturers’ installation and warranty requirements. Because of the lower flue gas temperatures and lesser heat transfer they are less likely to catch surrounding combustible material on fire. Those that are used with solid fuel-burning appliances do, however. If combustible materials are in contact with the chimney there are provisions that allow the liner to be installed in what is defined as a zero/zero install. That means there may be zero clearance to the interior of the chimney and zero clearance to the exterior of the chimney . The insulation may be of the blanket type or an expanded mica or masonry insulation. There are some manufacturers that will list a liner for use without insulation if it conforms to the NFPA 211 construction requirements. The problem is that it is almost impossible to determine that without destroying the chimney. It makes much more sense to insulate every liner serving a wood burning appliance. Even gas and oil-fired appliances that are vented into an exterior chimney will benefit from insulating the liner.