Masons & Do-It-Yourselfers

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. Not to be confused with traditional fireclay mortar, major building codes now require refractory mortar for these types of installations, so when installing or repairing fireplaces or brick ovens, make sure you use the product that meets the code requirements and is easy to use. Heat Stop has been tested to ASTM C-199 medium duty and meets ASTM C-1283 requirements. All Heat Stop products resist temperatures well in excess of 2,000 degrees – so you will be less likely to have reoccurring problems. A 50-lb. bag yields approximately 60 lbs. of refractory mortar. A 50 lb. installation will lay up about 100 firebricks with joints 1/16″ to 1/8″ thick. Overnight drying is usually sufficient for any Heat Stop installation. Visit our product section for more information. Heat Stop products can be purchased anywhere clay flues and firebrick are sold.