Titebond WeatherMaster Concrete Joint SL Sealant is a one-component, self-leveling, premium grade, high performance advanced polymer sealant which is specifically engineered for contraction/expansion joints and cracks in concrete decks and floors. Concrete Joint SL also works well for radon applications. Concrete Joint SL Sealant is designed to flow easily and smoothly into concrete cracks and joints, providing a permanent and durable seal.