BOSS - 03422BK10 - 139 Hi-Temp Mortar, Black

Item: BOSS13910
MFG: 03422BK10
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Hi-Temp Mortar, Standard Cartridge, Black


Boss® 139 Hi-Temp Mortar Is A Non Combustible Silicate Cement That Can with Stand Extremely High Temperatures. Formulated For Repairing Chimneys, Fireplaces and Sealing Wood-Burning Stoves and Appliances, This Product Has Strong Adhesion and Sets To Become Rock Hard When Fired.

Boss® 139 Hi-Temp Mortar Cannot Be Used In Areas Where There Is Constant Movement, or Where Wet Conditions Exist or May Occur.

Boss® 139 Hi-Temp Mortar Has Been Tested and Exceeds Astm E-136. 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.


  • Can with Stand Extremely High Heat
  • Apply Using A Standard Caulking Gun
  • Dries Rock Hard When Cured and Fired
  • Safe To Use and Handle
  • No Harmful Odors
  • Water Clean-Up (Prior To Curing)
  • Voc Compliant
  • Contains No Asbestos Fillers Of Any Kind
  • Meets Residential Construction Code Approvals Including I.R.C.

California residents: see Proposition 65 Warning

Features and Specification

Functions Fire Block, Draft Stop, Sealing
Height 8.2500
Includes 4 Inch Nozzle
Length 2.0000
Application Hi-Temp Non-Combustible Mortar For Repairing Chimneys, Fireplaces, And Sealing Wood Burning Stoves And Appliances.
Brand BOSS®
Comments/Notes Can Contribute Credits
Composition Silicate Cement
EAN 0787930139108
UL Recognized No
Temperature Range 0°F to 800°F (-17.7°C to 426.6°C)
Type Fire Block
UL Listed No
Size 10.1 Ounce
UPC 787930139108
UV Resistant No
Width 2.0000
Standards ASTM E-136, IBC/IRC, BOCA National building Code, CABO one and two family dwelling code, UBC Section 796, BOCA-SBCCI-ICBO-NFPA Building Codes
Package Weight 18.0000
Package Height 9.3125
Package Length 5.8750
Package Width 7.8750
Weight 1.5000


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picture_as_pdf specification sheet