There are a lot of factors that can lead to the deterioration of a flue: Lack of maintenance, thermal expansion, freeze/thaw, erosions and acids in the exhaust. Whatever the cause, once a flue has been compromised, it needs to be relined. Whether the flue vents your fireplace or a heating appliance, a damaged flue can lead to exhaust gases entering the home, or high heat exposure to combustible materials. All of these can create dangerous environments.
In a furnace or heating appliance flue, the gaps and cracks inevitably occur over time in the flue. This can be from constant heating and cooling, the acid in the exhaust, condensation, or external factors. Once the seal of the flue is broken, exhaust gases such as carbon monoxide can escape into neighboring flues or adjacent living spaces. Carbon monoxide poison can be fatal. and can be caused by gases entering the home through damaged or over/undersized flues.
If you are having a gas appliance removed, replaced or repaired, you should contact a chimney professional to inspect the flue to make sure the flue is in safe working order and is the appropriate size for the appliance(s) using it.
We reline our flues only with UL Listed components, per the manufacturer's specifications. They all come with a lifetime warranty and ensure you and your family a safe, sealed flue throughout the years.