This volume contains the proceedings of the Second International Symposium on Durability of Building Sealants, held under the joint auspices of the British Building Research Establishment Ltd (BRE) and the International Union of Testing and Research Laboratories for Buildings and Structures (RILEM) Technical Committee 139-DBS. The twelve contributions in this volume reflect the wide spectrum of current research and provide for the development of an International Standard on Sealant Durability.