Flue sizing, direct connects explained, and other in-depth technical explanations.
When a wood stove is hooked into a thimble, (a round opening where a woodstove connects to a masonry chimney, usually made of terra cotta or metal) running directly into a terra cotta lined chimney, sometimes the flue is too big for the appliance to draft properly. NFPA (the National Fire Protection Association) standards require a…
In houses built prior to the 1950s, masons often did not use terra cotta flue liners. Chimneys that are brick, stone, or concrete block only, without terra cotta flue tiles, are unsafe for use. Gaps form where mortar has fallen out, and these gaps may allow excessive heat to come into contact with combustibles, or noxious…
A direct connect is when an insert or a woodstove is installed into a masonry fireplace without a full liner. Instead it will have a short length of stainless liner (often an oval or rectangular shape) extending just to the bottom of the flue (the terra cotta tiles).While building code allows for a direct connect,…