Bostik Seal 'N' Flex® 1


Please note, this product is BOX BUY only.

Bostik Seal 'N' Flex® 1 is a low modulus, one-component, Class-A polyurethane sealant. It offers smart advantages such as low modulus, ±50% joint movement capability, excellent durability, and acoustic rating. The sealant is non-staining and paintable* and is available in 12 popular colours. Made in Australia, it provides a tough and flexible seal capable of cyclic expansion and compression movement of 100% (±50%) of the original installed joint width.

Product Characteristics:

  • Colors: Black, White, Grey
  • Size: 300ml Catridge, 600ml Sausages

Applications of Seal 'N' Flex® 1 Polyurethane Sealant

Bostik Seal 'N' Flex 1 can be used on:

  • Insitu concrete and render
  • Precast and tilt-up panels
  • Brickwork and blockwork
  • Plasterboard face and paper-lined recessed edges
  • Fibre cement sheet
  • Aluminium windows
  • Granite, sandstone, and marble
  • GRC, fiberglass, and most specialty panel systems

Classification Standards

Bostik Seal 'N' Flex 1 meets the following standards:

  • CSIRO RILEM Long-Term Sealant Durability Study DBCE Doc. 97/196 (M)
  • DIN 18540 (German) and SNJF (French) approval as a low modulus external joint sealant
  • AS4020 Potable Water
  • ASTM C.920-87 & 98 (USA) as Type S, Grade NS, Class 50, use NT, G, A, M, & O as an external joint sealant
  • AS1157-1972 Resistance to fungal growth. Ministry of Agriculture and fisheries New Zealand (Meat, fish, Game, Poultry- All areas)

Cleaning of Seal 'N' Flex® 1 Polyurethane Sealant

It is recommended to use protective goggles, barrier creams and ointments, gloves, and protective clothing. Cured material can only be removed by mechanical means. Clean off uncured material and equipment immediately after use using Bostik Handy Wipe towels to remove adhesive from the skin.


Bostik Seal 'N' Flex 1 can be painted after a minimum of 7 days. Coatings containing solvents such as enamels, oil-based, or other coatings may cause the surface of the sealant to react, creating a tacky surface. Surface coatings may discolour in direct contact with cured Bostik Seal 'N' Flex 1. Surface coatings may crack and craze due to cyclical movement of the supporting sealant joint. It is recommended to perform a field test to ensure compatibility of any coating with Bostik Seal 'N' Flex 1.

Limitations of Seal 'N' Flex® 1 Polyurethane Sealant

Bostik Seal 'N' Flex 1 is not recommended for the following:

  • Use in chlorinated water such as swimming pools, spas, etc.
  • Use on any material containing bitumen
  • Constantly immersed saltwater
  • Glazing applications
  • Application to cement-based substrates within 28 days of initial pour or set
  • Use in trafficable joints
  • Applied in temperatures below 5°C or above 35°C
  • Exposure to water and/or alcohol before it has completely cured
  • Finished using wet tooling techniques, using solvents, water, or detergent/soap solutions
  • Applied to joints less than 5mm in width and 6mm in depth
  • Applied on joints larger than 50mm

Bostik Seal 'N' Flex 1 White may yellow on the surface if exposed to strong natural or artificial UV light for prolonged periods of time. Composite metallic façade systems can be subject to significant daily cyclical movement due to temperature variations. Crimping and bulging of the installed sealant before full cure may permanently deform the sealant's finish prior to full cure, especially on Northern and Western elevations in full sunlight. Refer to Bostik V70 Silicone Technical Data Sheet as a recommended metal façade sealant.

Storage and Shelf Life

Store Bostik Seal 'N' Flex 1 in a cool (between 5°C to 30°C), dry, well-ventilated area out of direct sunlight. Store away from oxidizing agents and acids. The shelf life is 24 months in the original unopened container.

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