A brief summary of the science involved in controlling heat, moisture and air movement in buildings is presented at the outset of the course. With this background, methods of designing enclosures for cold, mixed, and hot climates are examined. Design principles related to the design of walls, windows and roofs are presented and applied. In particular, topics related to the control of rain penetration, air movement, and interstitial condensation are studied in detail. Emphasis is placed on developing designs based on fundamentals which can be verified with computer modelling solutions.