Chimney lining is the most important piece of the chimney. It is the part that protects the chimney from overheating or catching fire. Popular liner materials are aluminum and stainless-steel. Though metal and stainless-steel liners often last long, over time sulfur and water mix inside the chimney, and the mixture starts to corrode the liner resulting in the liners pulling away from the framing and walls.
Before the 1900’s clay tiles were the quality. Masonry chimneys were tested by the National Bureau of Standards (NBS) throughout the Nineteen Eighties. Before the 1900s chimneys were lined with mortar. It had been determined that any unlined chimney would be extraordinarily unsafe to use.
Causes for Chimney Relining
A properly sized liner results in proper air control and an incorrectly sized liner will cause excessive creosote build-up in the chimney. Tests conducted by the NBS showed that flue gases entering into brick and mortar can decrease the usable lifetime of a chimney. This may cause harmful gases to leak into the living space of a home.
Chimney Liner Types
- Cast-in-Place Liners.
Cast-in-place liners create a seamless, sleek interior that is easy to take care of. It reinforces a worn, weakened chimney structure. This method is good for multiple flues within a chimney.
- Clay Tile Liners.
They are inexpensive, readily available, and work best with open fireplace chimneys that are properly maintained. One disadvantage to clay tiles is they do not absorb and distribute quickly so the heating is uneven. This will cause them to eventually crack and split apart thus resulting in earlier replacement.
- Metal Chimney Liners.
Typically made of stainless steel or aluminum are primarily used to upgrade and repair existing chimneys. They are ranked extremely high for safety and durability and are often used when replacing existing liners. Stainless steel works well with wood-burning, gas, or oil applications and aluminum is an inexpensive alternative for certain medium efficiency gas applications only.