A safe, compliant chimney lining is mandated in most fire codes as a result of extensive testing by the National Bureau of Standards (NBS) to address concerns about durability, performance, and safety. Therefore, in a contemporary masonry chimney, the flue lining is made of terra cotta, ceramic or metal, and serves several functions:
1. It contains combustible products and leads them outside of the house into the atmosphere, protecting the house.
In the NBS tests of unlined chimneys, adjacent woodwork caught fire in only 3 1/2 hours, which is why an appropriate liner is so very important.
2. A safe, code-compliant liner protects a masonry chimney's walls from heat, potential damage, and corrosion from combustion byproducts.
The NBS tests revealed that in unlined chimneys, highly acidic flue gases often penetrated the brick and mortar, eating away at the chimney's mortar joints, and allowing heat to transfer more rapidly to nearby combustibles – which means that dangerous gases such as carbon monoxide can leak into the living areas of the home.
3. Liners contribute to optimal efficiency for your appliances.
The key to maximized performance in most oil/gas furnaces and modern wood stoves is a correctly sized flue. Why? Because in addition to leading the products of combustion out of the house, the chimney draft also supplies combustion air to the appliance. If the liner is correctly sized, it prevents excessive soot buildup in wood-burning stoves and minimizes the production of carbon monoxide that can occur with conventional fuels.
The "Big 3" categories in chimney liners.
Old, damaged or unlined chimneys are potentially hazardous. There are three main liner options we offer to keep your chimneys working well, and your home safe. We recommend that you have your chimney inspection done regularly by our chimney professionals, to ensure it meets modern safety standards.
1. Clay tiles.
Inexpensive, easily obtained, and high on performance, clay tile chimney liners are the most popular choice for liners in today's marketplace. They are, however, vulnerable to splits and cracks, and must be checked regularly and repaired if necessary. We are fully equipped to do that for you.
2. Metal chimney liners.
Used primarily in liner upgrades and repairs, stainless steel or aluminum liners provide safety, performance, and durability. Stainless steel liners are used for wood-burning fireplaces, oil or gas furnaces. Aluminum is used as an inexpensive alternative for medium efficiency gas furnaces. High heat-resistant insulation is used with metal liners to help ensure safety and enhance performance.
3. Cast chimney liners.
Cast-in-place cement liners create a smooth, insulated passageway for flue gases. This form of liner can actually improve the integrity of older chimneys and is for use with all types of appliances and fuels.