Willseal 600 : Self-Expanding Resistant Joint

  • Vertical expansion joints
  • Joints in pre-cast concrete, masonry, and facades
  • Roofing and insulated metal panels
  • Exterior insulation finish systems (EIFS)
  • Primary seal in starter track assemblies for window wall

Data Sheet


Willseal 600 is a UV stable, pre-compressed, self-expanding, flexible, flameresistant joint seal. It is a high-density polyurethane foam that is impregnated with a modified acrylic resin and treated with a pressure-sensitive adhesive on one side for ease of installation. Willseal 600 self-expands to fill the joint creating an elastic, vapor-permeable, weathertight seal. Questions? Contact Us.

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Willseal® 600 & 600S is a pre-compressed, self-expanding foam joint sealant, engineered to perform as a highly flexible, weathertight, primary or secondary seal in vertical exterior applications. (600 for primary or secondary; 600S in secondary only).

600S is specifically designed to provide the ideal foundation for a large variety of wet sealants, such as silicone, polyurethane, polysulfide, and acrylic. Unlike conventional wet sealant and backer rod methods, Willseal 600 & 600S is not susceptible to breakdowns caused by excessive or rapid joint movements, thus protecting structures against rain, wind, dust, and sound. Willseal 600 & 600S is waterproof to a wind-driven rain at 12.5psf (70mph) yet it is vapor permeable, making an optimal addition to any air barrier system, cavity wall joint, and interior partition application.

When used within its application range, Willseal 600 is weathertight against driving rain up to 12 lb/ft² psf or 600 Pa. Remains permanently flexible.
• Low volatility.
• Compatible with several Tremco Sealants.
• Chemically compatible with many types of commercial construction substrates: will not corrode iron, zinc, steel, galvanized steel or copper, and will not chemically harm concrete, lightweight concrete, mortar, brick, natural stones, plexiglass or wood.
• Minimal surface preparation required.
• No mixing or masking.
• Can be applied in various weather and temperature conditions.
• Easy soap-and-water cleanup: no solvents, no cartridges, no pails.
• Compatible with most porous or sensitive substrates.
• Proven wind driven rain resistance since 1965
• Depth of seal can be changed to increase R-value

Willseal 600 is available from your authorized Tremco distributor, and directly through Tremco and Willseal sales representatives