Because of their size and beauty, or because of location, restoring historic homes has become the trend. These homes must not only be cosmetically restored but also functionally restored to meet current building codes. As part of the process of restoring these majestic fireplaces, Chimney Restoration allows homeowners to use their fireplaces in a safe & practical manner again.
In historic homes, the burning of high-temperature heating appliances such as wood and coal can cause difficulties due to the lack of clearances to combustibles. Many homeowners & historical societies consider Chimney Restoration to be an important part of the Historic Restoration.
Chimneys deteriorate from the inside out because of acidic gases, soot / creosote or condensation. In historic homes, the mortar used has a high lime content; therefore, when it gets wet, it resoftens due to moisture. Eventually, the moisture will deteriorate the mortar, allowing heat and gases to enter the structure through gaps or missing joints within the venting system.
Ninety percent of historic homes have wood in direct contact with the chimney. When wood is new, it has a flash point of 414 degrees F. Subjecting it to heat dries the moisture out of the wood, lowering the flash point to as little as 200 degrees F. This process is known as pyrolysis which occurs from continuous heating and cooling. In many cases this will be seen as charred wood behind plaster or the mantle surround.
An early means of restoration was dropping clay flue tiles in the unlined chimney. This type of reline does not allow any air space as an insulator to the existing walls of the chimney. There is also no guarantee the tiles are seamless as many of these chimneys were constructed with offsets throughout the home. These gaps allow gases and creosote to escape the venting system and increase the likelihood of a chimney fire. After a chimney fire, people often look down the clay tile liners and see only hairline cracks, so they then assume that it’s safe to continue using the chimney. What they don’t take into consideration is that, once the flue gas temperatures rise, those hairline cracks can expand as much as one quarter inch, allowing creosote to leak out behind the liner even more.
If a chimney fire occurs after this, the situation would be the same as having a chimney fire in an unlined chimney, possibly resulting in a structure fire and endangering the safety of everyone in your household. In a research project conducted by the Housing and Home Finance Agency, it was noted that tile flue liners will crack when temperatures reach 1400-1700 degrees F. Chimney fire temperatures can reach as high as 1900-2000 degrees F.
Another hazard involving tile flue liners is that they have a tendency to shift, thus leaving an opening between the liners, which allows creosote to leak out. Very often we have found a large build-up of creosote behind the flue liner. If you should have a chimney fire, the fire will spread from the flue liner into the casing.
There is a great need for consumer education on the topic of chimney problems and proper solutions. Have your chimney cleaned once a year, and do not let any possible damage go unattended.
We recommend using a cast-in-place cement lining system to reline any historic chimney. This system allows us to size the flue to the fireplace opening to insure proper draft. This system provides a solid, seamless flue to last for many years to come. With no areas for gases to escape, no heat radiation or creosote leakage can occur. This system allows owners to breathe life back into property by adding the element of fire as it was intended.
Call or e-mail us if you have a question or would like a quote. With over 45 years of combined experience, our corporate office personnel will be able to accurately advise you as to your best course of action. Don’t take chances with your family’s safety!