Specified Technologies SpecSeal® Mortar Firestop

The Combination of Heat Sinking and Insulating Properties Provides an Effective Level of Fire Resistance

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What's special about this firestop mortar?

  • Firestopping for construction gaps and blank openings to protect from smoke and flames, as well as noxious gases
  • Lightweight mortar is fast drying, so forms come down quicker to complete the job faster
  • Excellent for retrofit, due to its low density and ease of use
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SpecSeal® Firestop Mortar is a cost effective, lightweight portland cement-based firestop sealant that provides an exceedingly high level of protection and resistance to fire.


STI-SSM22B SpecSeal® Firestop Mortar Bag Bag 22 lbs
STI-SSM106 SpecSeal® Firestop Mortar 6 Gal Pail Pail 22 lbs

You can apply this mortar by pouring, pumping, or troweling, to meet your preferences and needs. Its lightweight and low-density properties mean that you don't have to spend much time forming your jobs with support, and allow you to perform retrofit jobs very easily. Mortar is designed to dry quickly, and will not crack or spall due to freezing or changes in temperature.

This particular firestop has been created in such a way that it not only seals off the spread of fire and hot gasses but also minimizes the amount of heat conducted through the assembly. In addition, it has been created specifically for applications in which the openings are medium to large sized.

SpecSeal® Firestop Mortar is the basis for systems that meet the exacting criteria of ASTM E814 and UL1479

  • Less forming and support needed than with other types of firestop, for easier applications
  • Can be used with firestop collars and wrap strips for maximum protection
  • Highest yield per pound means you will save money on each installation for total labor savings
  • Can be used on countless applications, including aluminum cable tray, metallic pipes, cables, steel cable trays, and combustible penetrants such as plastic pipes or insulated metallic pipes (when used in conjunction with other SpecSeal® intumescent products)
  • The red color allows you to quickly and easily spot the mortar when performing routine inspections
  • Because the mortar adheres to chemicals, you do not need to spend the time or money on concrete fasteners



  • Large openings through concrete floors and walls
  • Cable trays
  • Bus duct
  • Multiple pipes
  • Insulated pipes
  • Plastic pipes
  • Cables


Color Pale red
Flame Spread 0
Smoke Developed <5
Odor No perceptible odor
Density (as shipped) Bulk approx. 0.45 – 0.55
Density Mixed (wet) 0.80g/L ± 0.03 (6.4 – 6.9 lb/gal)
Density (dry mortar) .065 g/L (5.4 lb/gal, 40.5 lb/cu ft)
Ratio Water/Mortar 14.3/22 to 17.6/22
Yeld (per 22 lb) 1,250 – 1,425 cu in (20.5 – 23.4 L)
Shelf Life No limit
Application Temp. 35°F – 100°F (2°C – 38°C)
Open Time 30 minutes working time
UL listed UL1479, ASTM E814



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