RUTLAND Dry Mix 211 is a refractory mortar ideal for joining or repairing masonry flue tile in any gas or wood fireplace and wood, coal, or pellet stove chimney. Just add water, mix, and trowel on to seal and join flue tiles. It can also be used as a parge coating (thin over-coat) when building fireboxes to give your fireplace a nice, even, dark gray finish. Does not require (but is stronger with) heat curing. Meets NFPA 211 standards and NYSCMA Tek Spec.