Selleys Butyl Mastic is a synthetic resin, butyl rubber based mastic which forms a smooth tough skin, but remains permanently plastic underneath. It is available Off White.


  • Remains permanently plastic under a smooth tough skin
  • Versatile sealant with excellent adhesion to a variety of substrates without the necessity to prime
  • Will not bleed into porous surfaces
  • Non-sag in joints up to 12mm vertical joint
  • Wide service temperature: –35° to +65°C
  • Excellent weathering characteristics
  • Does not corrode metals
  • Good water resistance
  • Life expectancy is approximately 5 years in a thick joint. It is recommended to use silicone sealant in thinner joints
  • Easy smoothing and clean-up with mineral turps or white spirits

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