The Canadian Mortgage and Housing Corporation (CMHC) has determined that the window to wall interface is the major contributor to moisture problems in buildings. EnvelopeSealant (TM) is an elastomeric co-polymer thermal plastic that acts as a primary barrier to moisture and air penetration at the window to wall interface. Its physical properties allow it to adhere to most surfaces while staying flexible over a wide range of temperatures. These characteristics enable the product to move and adjust with building settling, while maintaining a watertight seal around building openings. Use of Envelope Seal is part of the Built Green initiative, and contributes to reducing new home warranty claims while improving air tightness by as much as 43%.