3M™ Fire Barrier Mortar is a lightweight, gypsum-based powder that mixes with water to form a heat-absorbing firestop for through penetrations in fire-rated floor or wall assemblies. Versatile mortar can be mixed self-leveling or non-sag, and adheres to a range of construction substrates and penetrants. It also acts as a heat sink, reducing the chance of fire on unexposed sides of the assembly.

A Firestop that Can Take the Heat
For mechanical and electrical through penetrations where the penetrants may generate heat, our 3M™ Fire Barrier Mortar provides a ready-to-mix solution. This gypsum-based mortar acts as a heat sink, absorbing heat from penetrants and reducing the chances of combustion inside firestopped floor and wall assemblies.

Recommended Applications


Firestopping and sealing mechanical and electrical service penetrations
Blank openings and large annular spaces
Floors and other applications requiring self-leveling material
Vertical and horizontal substrates requiring non-sag adhesion


Fully Tested and Approved
3M™ Fire Barrier Mortar is firestop tested up to 3 hours in accordance with ASTM E 814 (UL 1479) and  CAN/ULC-S115 when installed in listed systems, including 2-1/2” (63.5 cm) minimum thickness concrete floors. It is also tested in accordance with AS1530.4, EN1366 and ASTM E814 (UL Listed) and has proven self-bonding during fire testing.

Easy and Safe to Use
The firestop mortar comes ready to mix with potable water, making it fast and cost-effective. Versatile material can be mixed to a thinner consistency for self-leveling applications such as floors, or as a non-sag material for vertical walls. It adheres well to range of common construction materials including concrete, metals, wood, plastic and cable jacketing. The mortar is pumpable as well, resulting in faster work times and lower labor costs. It cleans easily with water. Polypropylene-fiber reinforced material reduces cracking during cure time. The cured material is paintable after priming. It is also re-enterable, allowing technicians to easily access components after installation with a common hole saw.

This mortar contains no asbestos, halogens, Portland cement or MMMF and requires no fibrous damming materials or procedures.

The Science of Better Fire Protection from 3M
Since 1925 when one of our lab assistants invented masking tape, 3M has been applying science to life –developing adhesive products and technologies that help entire industries and individual businesses worldwide. The work that began with a single 3M engineer now spans decades and generations. And all of it goes into each of our adhesives, sealants, protective coatings and firestop materials like 3M™ Fire Barrier Mortar – to improve performance, and to help businesses like yours operate faster, better and more efficiently.

• Ready-to-mix pumpable mortar is deal for firestopping large annular spaces and floors
• Lightweight mortar designed to absorb heat, reducing chance of combustion on unexposed sides
• Polypropylene-fiber reinforced powder mixes with water for self-leveling or non-sag applications
• Contains no asbestos, MMMF or halogens
• Firestop tested for up to 3 hours in accordance with ASTM E 814 (UL 1479) and CAN/ULC-S115

• Color: Off-white
• Package Quantity: 1 BAG
• Part Number: MORTAR
• Product Type: Mortar