If you are unable to fit the correct size round chimney liner down your chimney you are not necessarily out of luck. The next best liner to look at is a rectangle, square or oval shaped chimney liner. It is important to avoid reducing the size of the chimney liner just to be able to fit it down your chimney. Reducing the size of the liner will hinder the draft of the appliance and cause a wood stove to spill smoke. For example, if a 6" liner is needed, and your flue size measures 5.5" x 11", the 6" liner will not fit. However, a 4.5" x 9.1" oval liner will fit down the flue and it has the direct equivalent of a 6" round liner. Other shapes such as rectangle and square liners are also available. For help choosing a chimney liner, please visit our Flue Liner Size Guide & Liner Shape Conversion Guide.Another way to accommodate a liner down a chimney is to remove the existing clay terra cotta flue. Once a flexible liner is installed in the chimney, the existing clay flue is now void. There are tools available to rent or purchase to help remove a clay flue known as tile breakers. A tile breaker is a heavy steel plate or chain assembly that attaches to steel rods & drill so you are able to pulverize the flue out. Steel rods, similar to chimney cleaning rods, will attach to the drill and to the tile breaker. Once the flue is broken up, you are able to remove the pieces through the clean out trap. Unlike brick, terra cotta tile is very fragile and easy to pulverize without causing damage to your block or bricks.Another way to accommodate a liner down a chimney is to remove the existing clay terra cotta flue. Once a flexible liner is installed in the chimney, the existing clay flue is now void. There are tools available to rent(opens in a new tab) or purchase(opens in a new tab) to help remove a clay flue known as tile breakers. A tile breaker is a heavy steel plate or chain assembly that attaches to steel rods & drill so you are able to pulverize the flue out. Steel rods, similar to chimney cleaning rods, will attach to the drill and to the tile breaker. Once the flue is broken up, you are able to remove the pieces through the clean out trap. Unlike brick, terra cotta tile is very fragile and easy to pulverize without causing damage to your block or bricks.