Everflex Fire Mate Intumescent Sealant from Everbuild is an acrylic sealant that swells when exposed to temperatures in excess of 125°C to prevent the passage of fire and smoke and has a fire rating of up to 4 hours in certain joint configurations. Used for sealing joints, voids and irregular holes in fire walls, partitions and other structures as well as internal perimeter pointing of fire rated door and window frames.