HeatShield PriorFire Formula 51 can be parged, troweled, or hand
packed over any brick, block, or stone surface that has been
exposed to high temperatures such as smoke chambers, ash pits,
vent connections and more. Formula 51 meets all national and
local building codes for new construction and masonry fireplace
& chimney repairs. Formula 51 is not suitable for food storage or
food preparation areas. In addition, Formula 51 meets ASTM C-199
(Medium Duty), and is non-water soluble when dry.
