Do I need to line the chimney for my new woodburner?
It is strongly advised to line the chimney when installing a new woodburner or multifuel stove. Many modern stoves are operating at efficiency ratings of over 80%, which means that nearly all the combustible material in the stove is being burnt. This leads to a cleaner emission from the chimney, but produces high volumes of water in the form of steam in the process. In a lined chimney this is contained within the liner becoming water as it condenses as it cools but is eventually exhausted from the chimney. In an unlined flue, the steam condenses on the original chimney walls and the resultant water, instead of being retained in the flue, is absorbed by the masonry. This water then slowly permeates through the mortar/masonry to show up as a brown patch on the chimney breast in the room, usually in the bedrooms first. Once this has occurred it is very difficult to eradicate.
