Flexible & Rigid Liners

Let’s start with the obvious differences in the Flexible Rigid Chimney Liner compare. First of all the Rigid chimney liner can only be installed if your chimney is straight. If it has any turns in it your answer is obvious which chimney liner you need. But if your chimney is straight you have an option. This is because flex chimney liner is made from stainless steel .005” or .006” thick compared to the rigid that is 24-guage (0.024 in.) or 22-guage (0.029 in.) stainless steel. Is it worth spending the extra money for a rigid stainless steel chimney liner?

If you are installing this chimney liner in chimney that is used with an appliance that is your main source of heat, we highly recommend the rigid chimney liner system. Especially if you are using a solid fuel burning appliance, such as a wood or coal stove.

The second difference is the amount of fly ash or creosote that collects inside the chimney liner. The flex chimney liner has corrugations inside it, like small shelves for the creosote to collect on. When creosote is hot, it is actually a liquid. So when the creosote is dripping down the inside of a flex liner it is constantly running over these corrugations and slowly building up, making the chimney liner opening smaller and smaller as the creosote thickens. The rigid chimney liner also has the creosote running down the inside but now it has a perfectly smooth surface. This means that a lot of the creosote will drip back into the appliance or fireplace and be re-burned.

A third advantage is the draft. The draft in a smooth inner wall chimney liner, such as the rigid chimney lining system, is 20% better compared to a corrugated chimney liner. This means your furnace, fireplace, wood/coal stove will have a stronger draft. If you are having problems now with your draft installing a round rigid chimney lining system will definitely improve it.

A fourth advantage is the cleaning. With a flex liner you need to purchase a special poly brush to clean the chimney liner. This is because a normal metal one will damage the chimney liner. When you need a heavy cleaning, which is likely with a corrugated chimney liner, you need to use harsh and expensive chemicals to soften the creosote to be able to remove it. If you have a rigid chimney liner you can be as aggressive as you want. You can use a metal brush and even have a very aggressive cleaning done called a Roto-Cleaning. This involves a steel cable and a high speed drill. Do not even think about this with a flex liner. After a cleaning with the Rigid chimney liner, you can make it shine like new.

One last advantage we will mention is the outside diameter or the rigid chimney liner compared to the flex liner. If you need a 6” liner and your chimney opening is 6 ¼”, you need to use the rigid liner. The flex liners are measure for inside diameter. Once you add the corrugations on you add about 3/8”. This means a flex chimney liner will not fit but the rigid chimney liner will.

Final outcome of the Flexible Rigid Chimney Liner Rigid WINS!!! If you want the best product out there to protect your family and home, Rigid is what you need.