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Stone Mason® Fire Block

Product Description
Installation and
Technical Literature
Application Tips
and Instructions

Stone Mason® Fire Block is a repair mortar and sealant designed to seal fire-rated service penetrations and construction joints in horizontal and vertical fire separations. ASTM E-136-compliant, Stone Mason® Fire Block is ideal for use around wires, pipes, duct work and vents in wood or steel framed non-rated construction, as well as fireplaces, furnaces and chimneys.


  • Seals fire-rated service penetrations and construction joints
  • Adheres to wood and most common masonry materials
  • Resists smoke and temperatures up to 2000°F
  • Water-based, non-combustible


  • Approximately 0.4m2 (4 sq ft) at 3mm (1/8”) thickness

To ensure our customers always have access to the most current information, we ask that you contact the Henry Company Customer Support Center at 1-800-486-1278 for more information about this product.


All Surfaces must be dry and frost free. Remove any oil, grease, rust, dirt or other contaminants that may inhibit proper adhesion.


Apply Fire Block Mortar with a trowel or putty knife. Tool mortar surfaces to a smooth defect-free finish using a slightly wetted trowel or putty knife.


FOR INTERIOR APPLICATION ONLY. Not to be used in areas where there is continuous vibration on the penetrating item. Do not expose to water. Do not install when surface and air temperatures are below 0°C (32°F). Do not apply to frozen surfaces. Prior to use on plastic test for adhesion and compatibility.


Approx. 0.4 m2 (4 sq. ft.) at 3 mm (1/8”) thickness.


Clean all equipment immediately after use with soap and water.


Wash thoroughly after handling. In case of eye contact, flush immediately with water for 15 minutes and call a physician. Keep out of reach of children. Keep from freezing. Not for internal consumption.

The consumer shall satisfy themselves of the suitability of this product for the intended purpose. Weather, applicator's skill and surface conditions are beyond manufacturer's control. We, therefore, limit our liability to replacement of defective material only, within one year of proof of purchase.