Interior Acrylic Fire Sealant

Bostik Firecaulk is a fire rated acrylic (water based) gun grade mastic with limited joint movement capability.


Bostik Firecaulk is a single component, non-sag, fire rated acrylic based gunnable sealant. A general purpose product for construction joints and the sealing of service penetrations in plasterboard, concrete floors and masonry wall constructions.
Bostik Firecaulk is a gun grade acrylic based sealing compound specifically manufactured for sealing low movement interior joints (less than 5%) in masonry and plasterboard to provide a fire barrier for periods up to 4 hours.


  • Sealing of gaps around pipes, cables, ducts and services which penetrate fire rated walls and floors.
  • Fire rated cable penetration in concrete and masonry.
  • Installation of fire rated sealant in concrete walls and floors.
  • For vertical and horizontal joints, interior or exterior.
  • Application requiring acoustic properties or STC rating.
  • Sealing construction and expansion joints.
  • Sealing joints in pre-cast panels.
  • Perimeter sealing of door and window framing.
  • Sealing gaps between faced and cladding panels to various building materials.
  • For new construction and remedial applications.
  • To prevent the spread of fire and smoke through walls and floors.


  • Fire resistance when tested in accordance with AS1530.4-1998, BS476: Part 20: 1987 and AS4072.1-1992
  • Fire rating for gaps up to 50mm.
  • Designed for Australian conditions.
  • Good flexibility joint movement 5%
  • One part no mixing required.
  • Very easy to apply and gives a smooth finish.
  • Smooth gunnability and tool off finish
  • Low odour
  • Non-toxic
  • Asbestos free.
  • Priming not normally required.
  • Water clean up.
  • Prevents the passage of hot gases.
  • Paintable after 24 hours at 20'C.
  • Water resistant after cure (7 days after application).
  • Excellent adhesion to metal, wood, plasterboard and all masonry
  • Acoustic capabilities with STC rating in plasterboard construction.
  • Available in two colours, white and limestone

Comparison with traditional systems:

CharacteristicsTraditional SystemsGeoplast Reusable Formwork
Hindrance-Modular system
ResistanceLimitedUp to 60 kN/m2
Concrete adherenceRequires dismantling agentsBeing made of plastics, GEOTUB PANEL does not stick to concrete
Protection10%The best protection for the columns until the end of the operations
PlumbingRequires long operations and it is often inaccurateQuick and accurate thanks to the external structure that allows easy shoring and plumbing
Dismantling agentsRequiredNot required. Everitt Site Supplies recommend 'Kleen Kote' protection and release formula to maintain your forms in top condition.