GacoFlex U91 is a single-component, moisture-cure aromatic urethane base coat with strong adhesion to numerous substrates. It produces a tough film that protects foam substrates and prevents oil migration on asphalt-based roofs.

U91 is not a finish coat. Top coat it with a GacoFlex aliphatic urethane, silicone or acrylic coating for weatherability, UV resistance and a high-reflectance cool roof. It is designed to rejuvenate and extend the life of aged asphaltic, single-ply and previously coated roofs.

Why Contractors Choose U91:

• Oil Migration Resistance: Excellent resistance on asphaltic roofs without bleed-blocking primers.
• Tough Protection: The tough cured film gives robust protection to foam roofs.
• Strong Adhesion: Exceptional adhesion to GacoPrime LVOC Primer, E5691 Water Reducible Epoxy Sealer/Primer and E5320 2-Part Epoxy Primer/Filler.
• High Solids: 80% solids by volume, with outstanding weatherability and chalking resistance.

Ideal Applications & Substrates:

• Aged Asphaltic Roofs: Rejuvenates aged asphaltic roofs and prevents oil migration.
• Single-Ply Membranes: Aged single-ply roofs, primed as described below.
• Foam Roofs: Protects polyurethane foam with a tough film.
• Previously Coated Roofs: Extends the life of roofs that already carry a coating.

Application Specifications:

• Mixing & Thinning: Mix thoroughly with an electric or compressed-air mixer. Thinning is typically required, using GacoFlex T5112 or T5120 thinner, but never more than 10% by volume.
• Application Rate: Sample rate 4.7 L per 9.3 m² (20 mil wet film). Do not exceed 5.7 L per 9.3 m² per coat.
• Dry Time & Pot Life: Dry time is 10-12 hours at 24°C and 50% RH. Pot life is about 2 hours at 21-27°C, up to 3 hours with 10% thinner. Contains a toluene diisocyanate prepolymer, so see the Safety Data Sheet.