Using the right Heat Stop refractory product is critical to the success of your project. How do you know which one to use? While there are a wide range of products available – premixes, castables and mortar – all have a role and specific type of use. How do you know which Heat Stop product to use? The answer can be found simply by following the manufacturer’s directions. Remember, not applying Heat Stop products correctly may lead to unintended results.

Heat Stop Pre-Mix

Heat Stop Pre-Mix products, which come in 15 and 50 lb. plastic pails, are used in interior applications as mortar – generally when laying up firebricks in a hearth or smoke chamber. (For example, it can used for installations or repairs in chimneys, boilers, furnaces, kilns and bake ovens.) It is a ready-to-use product, needing just a stir before using. Since it is water soluble in service (until it dries) it should not be used where excessive moisture is present. Once dried, it resists temperatures in excess of 2,000 degrees, and meets all local, regional and national building codes. It dries to a dark grey color just like regular cement mortar. Domestic Fireplace Mortar, another product made by the manufacturer of Heat Stop, is a similar pre-mix product, though it dries beige in color. Remember, Heat Stop pre-mix or Domestic Fireplace Mortar are products intended for interior (no moisture) applications. Using them in high moisture applications may not achieve the intended results. For exterior applications, it's important to only use Heat Stop 50 or Heat Stop II.

Heat Stop Dry Mix

Dry mix Heat Stop products – Heat Stop 50 and Heat Stop II – are designed to be mixed with water prior to using. They can be used when installing clay flu lining and firebricks in masonry fireplace and chimney applications, as well as in bake ovens. These economical dry mix products are the product of choice for interior or exterior (where moisture is present) applications. Heat Stop 50 comes in a 50 lb. bag, while Heat Stop II is provided in a 10 lb. pail. They dry to a light grey color.

Heat Stop Castables

Heat Stop castable products are used to cast special shapes. Heat Cast 40 is a medium weight refractory product that can be used when laying a foundation instead of firebricks in a hearth, or for casting sidewalls in a high temperature masonry application such as boilers or furnaces. It comes in a 40 lb. bag. Insul Stick is a medium duty refractory that can also be used to cast special shapes. It is most often used for insulating strength and cast be parged over firebricks in a fireplace smoke chamber. Insul Stick meets utility pass through requirements and can be used to seal wall penetrations. It can also be cast, troweled or sprayed. Finally, Insul Cast is an insulating refractory used most often to back-up other denser refractories such as firebricks or masonry. For example in a bake oven, it can be used under the hearth or over the dome for added insulation and strength.

It's extremely important to choose the right Heat Stop product for your projects. For more information, watch the video that appears in the Refractory Mortar section.

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