Intumescent Mastic Seals are very important for fire protection particularly if is an old building

Intumescent Mastic Seals help fill up any gaps on fire resistant walls and floors, between conduits and walls/floors and between fire resistant walls and structural supports. Fire Mastic cures to give a firm, but non hardening flexible seal in low movement fire rated joints to seal between joints in Fire Batts, substrate to penetration service applications and pointing up of penetration seals. Fire mastic may be used to provide a linear joint or gap seal with specific supporting constructions and substrates and as a penetration seal.


Safire     Nullifire     Rockwool     FSI


  • Flexible water based intumescent acrylic sealant
  • Tested to BS476 Part 20/22 & EN 1366-3, EN 1366-4
  • Up to 4 hours fire resistant
  • Long term flexibility
  • Excellent adhesion

Please contact Flame Stop Ltd on 01 8394005 for a quote for all your
Passive Firestopping requirements or email us at