Mulco Butyl is a Butyl rubber architectural one component sealing compound for exterior multipurpose. Dries by solvent evaporation.


  • No mixing or primer required
  • No staining of surrounding surfaces
  • Can be applied on vertical or horizontal, overhanging surfaces without subsiding or sagging
  • Remains flexible even at lower temperature
  • Withstands weathering
  • Good ultraviolet resistance
  • Compatible with Preserved Wood Foundation (PWF) requirements
  • Allows a joint movement up to ± 15% of the original width
  • Does not require painting, however it can be painted over 24 hours after application (latex paint).

Intended Uses

  • Used to seal outdoor joints between two perpendicular surfaces subject to thermal movements
  • For sealing joints around door and window frames, sidings
  • Good adhesion on many surfaces such as natural, painted or anodized aluminum, painted or stained wood, concrete or masonry
  • Can be used as bedding secondary seals or hidden join