The building envelope separates the interior from the exterior - it is our shelter from the elements, with layers to keep occupants warm, dry and comfortable.

The red line in the picture above shows a continuous layer that separates inside from out - this is the building envelope. The built components that make up this layer include:

• the STRUCTURE of the building;
• the CONTROL LAYERS - insulation, air barriers, vapour retarders, etc..
  • NOTE: the term "barriers" refers to the individual materials within the control layers;
    
• the interior and exterior FINISH LAYERS.