Foster® 65-05 F.R. C.I. Mastic is a high solids, fire-resistant, and weather barrier mastic used for protecting thermal insulation in outdoor service. It is an ideal surface coating for low-temperature insulating applications, replacing conventional asphalt cutback mastic due to its superior fire and weather resistance.

Specifications and Properties

• Color: Black
• Application Consistency: Trowel
• Average Weight/U.S. Gallon (ASTM D1475): 9.6 lbs. (1.15 kg/l)
• Average Non-Volatile (ASTM D2369): 66% by volume (76% by weight)
• Coverage Range: 12 gallons per 100 sq. ft. minimum (4.9 l/m2) for 0.192 in. wet film thickness
• Drying Time: Set to Touch in 6 Hours, Dry Through in 6 Days at 73°F (23°C) and 50% RH
• Service Temperature Limits: -40°F to 200°F (-40°C to 93°C)
• Water Vapor Permeance (Typical Average):
  • ASTM F1249: 0.03 perms at 1/8 in. dry film thickness
  • ASTM E96 Procedure A: 0.017 perms at 115 mils dry film thickness

Features and Application

• Fire Resistance: Suitable for use in fire-prone environments.
• Outdoor Rated and UV Resistant: Ideal for outdoor applications, providing protection against UV rays and weather elements.
• UL Certified: Produced under the classification and follow-up service of Underwriter's Laboratories Inc..
• Application Method: Apply with a trowel; not suitable for brush or spray application.

Key Data and Facts

• Wet Flammability: Flash Point at 106°F (40°C).
• Surface Burning Characteristics (ASTM E84): Flame Spread 35 when applied to inorganic reinforced cement board.
• Limitations: Not recommended for use on polystyrene foam; test compatibility with foil and paper facings.