This site has been optimised for the best experience on portrait mode, please rotate your device to continue.

All Products


BOSS® 354 is a high-quality joint and insulation sealant that has superior bonding strength and anti-bacterial properties. It provides a long-lasting, permanently flexible seal that can be used in internal and external sealing around window and door frames. The product exhibits good primer-less adhesion to concrete, plaster, brick, stone, masonry, aluminium, glazed tiles, metals, painted surfaces, coated or uncoated wood, and some plastics. The antibacterial properties protect the sealant from tarnishing and maintains elasticity after drying.


  • Easy to apply and good adhesion on many porous construction surfaces.
  • Flexible crack filler before painting jobs, for sealing construction frameworks.
  • Joint movement up to 15%.
  • Paintable post-application.
  • Waterproof, weatherproof, and aging-resistant.


  • Filling common connection slots during construction.
  • Installing and sealing uPVC windows.
  • Plasterboards, drywall panels.
  • Sealing the gap between the door frame and wall, foot baseboards & floor, and brick slots.


This product is available in white.


Available in standard 280 ml caulking cartridges.

Quick info

You may also like…