In historic homes, the burning of high-temperature heating appliances, such as wood and coa,l can cause difficulties in the following areas:
1) High Temperature Appliances & Unlined Chimneys
Chimneys deteriorate from the inside out because of condensation. In historical homes, the mortar 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.
2) Improper Clearance
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.
3) Chimney Fire
After a chimney fire, people often look down a clay tile liner 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.
If a chimney fire occurs after this, the situation would be the same as having a chimney fire in an unlined chimney, 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.
Call or e-mail us if you have a question. 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!
All Chimney Restoration specialists have been thoroughly trained in the art of chimney construction and are aware of present-day building codes, as well as your local codes.
Your Chimney Restoration professional will first inspect your chimney and perform a thorough cleaning. If necessary, they will also remove any clay tiles in preparation for the lining process.
An Inflatable rubber former is inserted into your chimney and held in place by spacers so that it is evenly spaced away from the walls of your chimney. The tube is then inflated to the precise diameter necessary for your appliance.
Our CRS-2000 mix, which is an insulated concrete that has been tested and approved for zero clearance to combustibles, is then pumped around the former. The mix hardens overnight to a perfectly fitted, seamless flue.
The next day the former is deflated and removed, and in such a short period of time, your chimney is restored to accommodate all fuels — at a fraction of the cost of rebuilding your chimney.
The tests on our CRS-2000 poured chimney liner were conducted at the Research and Development Laboratory of Chimney Restoration Systems, Inc., by Guardian Fire Testing Laboratories, Inc. these tests were conducted in accordance with the A.N.S.I. UL 1777 Zero Clearance Stardard for Chimney Liners and the CAN/ULC S635 for Masonry Chimneys.
CRS-2000 was tested to 2100 degrees Farenheit with wood in direct contact to the chimney: that is what we refer to as “zero-clearance to combustibles.” The same performance of this test further assures you that you have chosen the safest method available for restoring your chimney.