Chimney Lining Cone
This simple jobsite-built cone allows the deteriorated mortar on the inside of historic chimneys to be replaced rapidly. The cone is pulled up through the chimney flue with a rope on a wheelwell suspended from scaffolding above as thinned lime mortar is poured down onto it from above. In this way recessed mortar joints are pointed and the interior face of the chimney is parged in lime mortar, allowing the reuse of historic chimneys that might otherwise have been considered fire hazards due to mortar loss. Unlike popular modern ceramic and portland cement relining methods, this lime mortar treatment is compatible with porous historic brickwork. The soft rubber flippers on the bottom of the cone allow the cone to accommodate variability in the interior of the chimney, whether from irregular surfaces or from the flue narrowing as it rises. The cone has proven successful in relining both straight flues and those that curve as they rise out of the firebox and up through the smoke shelf. It takes about half a day to make a site-specific cone and reline the chimney. This method allows unstable chimneys that would otherwise be torn down and relaid to remain, saving both historic fabric and weeks worth of labor. If the rubber flippers are trimmed back, then they can also line the inside of chimney flue with a layer of lime mortar. (Preservation Science, 2019)