This paper documents the laboratory and exterior durability of high performance, Class 25 acrylic sealants. Commercial silicone and polyurethane sealants are used as controls. Laboratory durability is evaluated by measuring sealant flexibility, tensile properties and ASTM C920 and ISO 11600 joint movement capabilities. Many of these properties are measured both before and after 2500 hours of Weather-Ometer exposure. Exterior durability is assessed by monitoring 2 to 15 year exterior exposures in moving joints in low rise commercial buildings of brick, aluminum and Exterior Insulation Finishing Systems (EIFS) construction. Both laboratory and exterior durability measurements indicate that high performance Class 25 acrylic sealants have good joint movement capabilities, excellent weatherability and aesthetics, and are generally able to maintain an effective seal to a variety of substrates after extended exterior exposure. They perform and test in a manner similar to other Class 25 sealants of alternative chemistries.