Fire Mortar

BOSS 139 Fire Mortar is a non-combustible silicate cement that can withstand extremely high temperatures. Formulated for repairing chimneys and fireplaces and sealing wood-burning stoves and appliances, this product has strong adhesion and sets to become rock hard when fired. The product exceeds ASTM E-136 and can withstand temperatures of up to 3,000 degrees F. It can be used in wood-frame construction where an ASTM E-136 non-combustible sealant is specified and where allowed by the building code. This includes sealing around pipes, ducts, vents and chimneys at ceiling and floor level before drywall is applied.