Chimney Flue Liner Installation Types

A chimney frequently has more than one flue. For example, it is not uncommon to see in one chimney two or more flues, where one flue is for a fireplace and the other for an oil burning furnace.

There are several chimney flue liner installation types to choose from when either building a new chimney or installing a retrofit chimney liner. Each chimney flue liner installation type has its unique pros and cons.

Terra Cotta Chimney Flue Liners Terra Cotta chimney flue liner installation is commonly seen with masonry chimneys. Terra Cotta chimney flue liners are constructed out of sectional hard-fired clay tubular tiles that are orange in appearance. They can last for many decades, however they are susceptible to cracking under extreme and rapid temperature changes. Terra Cotta chimney flue liners are typically installed in sectional pieces as the masonry chimney is being constructed.

Aluminum and Stainless Steel Chimney Flue Liners

Stainless steel chimney flue liners are very commonly used today in zero-clearance fireplaces and with wood stoves, pellet stoves and gas stoves. Stainless steel chimney flue liners come in various sectional lengths and diameters. In addition, you can buy stainless steel chimney flue liners in straight, curved and flexible sections to fit almost any chimney application. Some stainless steel chimney flue liners are multi-layered so that cool outside air can be sucked into the stove or fireplace for promoting proper fuel combustion, and simultaneously hot combustible fuel byproducts can be expelled, all through the same chimney opening.

Stainless steel chimney flue liner installation is easy to do, however it should be left to the professionals to reduce the risk of fire and smoke inhalation risks. Insulation is typically required around a stainless steel chimney flue liner to help prevent heat transfer to the nearby framing structure of the fireplace and chimney. Aluminum chimney flue liners are typically used in limited gas stove applications. They should not be used with coal or wood burning stoves or fireplaces. Again, they should be installed by a professional and insulation should be installed around them when in near contact with framing structures.

Cast-In Place Chimney Flue Liners

Cast-in place chimney flue liner installation is typically reserved for older existing masonry chimneys. Cast-in place chimney flue liners involve inserting an inflated tubular bladder into the masonry chimney and then pouring lightweight heat-resistant concrete into the chimney. Once the concrete has begun to set, the bladder is deflated and removed leaving behind a seamless and cylindrical chimney flue liner.

A cast-in place chimney flue liner can help to improve the structural integrity of an old masonry chimney however it can also restrict air flow so extensively that it can virtually render the chimney and fireplace inoperable. Consequently, it is important to make sure a cast-in place chimney flue liner is sized appropriately to prevent this type of situation from occurring.

Another cast-in place chimney flue liner installation method utilizes a steel box with beveled edges at its top that is first lowered down into the chimney and then slowly raised up out of the chimney as the concrete is poured. This method creates a wider chimney flue liner opening, while at the same time providing additional structural integrity to the masonry chimney.

To conclude, before selecting a chimney flue liner installation method it is wise to first check with a chimney professional to see what is best solution for your particular chimney situation.