ELI5: Explain Like I'm 5

Building envelope

The building envelope is the outer “skin” of a building, like the walls and roof. Think of a giant jacket that your building is wearing. The building envelope protects the inside of the building from outside elements such as rain, snow and wind. It also helps to keep the inside of the building warm in the winter and cool in the summer. The building envelope is made up of many different materials like brick, wood, insulation and glass.