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Safire Intumescent and Acoustic Mastic is a flexible, waterbased, cartridge applied acrylic intumescent sealant.

Air curing, it forms a non-hardening flexible seal. When exposed to fire it will swell to 4 times its original size, creating a char, preventing the passage of fire, smoke and toxic gases for up to 4 hours.


  • Flexible water based intumescent acrylic sealant

  • Tested to BS476 Part 20/22

  • Upto 4 hours fire resistant

  • Long term flexibility

  • Excellent adhesion



Expansion/contraction joints, cartridge applied in gaps up to 35mm

Irregular or uneven gaps around door casings and window sills

Irregular or uneven gaps around service penetrations

Sealing fire protection boards and partitioning


Flexibility - Safire Intumescent and Acoustic Mastic is non-hardening, so will allow a degree of substrate movement. Resistant to cracking and splitting.

Excellent Adhesion - Safire Mastic is is formulated to give excellent adhesion to most building substrates including brick, concrete, steel and plaster without the use of costly primers.

Water Based - Safire Mastic is virtually odourless, and tools and equipment are easily cleaned without the use of solvents.

Environmentally Friendly - Safire Mastic is Halogen free and contains no fibres, so can be used with confidence.

Smooth Finish - Safire Mastic can be easily tooled to a smooth finish using a wet spatular if required.


Safire Mastic is extruded from a cartridge loaded into a standard skeleton cartridge gun.

1. Ensure all surfaces are sound, clean, dry and free from dust or grease.

2. Use the appropriate backing material to set the depth of the seal. Joint width or depth should be not less than 6mm so that there is sufficient material to give the movement required.

3. Gun in the sealant, taking care to avoid entrapping air or leaving gaps, and ensure there is a complete contact between sealant and substrate.

4. Tool down using a wetted spatular. Store in cool dry conditions.

See product data sheet here 

Safire Intumescent and Acoustic Mastic

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