More construction projects today call for indoor and outdoor brick ovens and fireplaces to expand living space. Building codes require refractory mortar for these types of installations, so when your projects call for fireplaces, chimneys or brick ovens, make sure the product your team uses meets the code requirements to avoid problems later on. Major building codes now require refractory mortar for these types of installations, so when installing or repairing fireplaces, chimneys or ovens, make sure you use the product that meets these code requirements. Heat Stop® Refractory Mortar is an easy to use, economical brand of mortar that can be effectively used in the installation of firebrick and clay flues, as well as in repair or restoration work. It has been tested to ASTM C-199 medium duty and meets ASTM C-1283 requirements, and resists temperatures well in excess of 2,000 degrees. A 50-lb. bag yields approximately 60 lbs. of refractory mortar. Visit our product section for more information. Heat Stop products can be purchased anywhere clay flues and firebrick are sold.