Building Envelope

Section 1: Envelope Performance Requirements

The building envelope is the critical interface between interior and exterior environments. It must simultaneously perform four functions:

1. Structural support: Transfer wind loads, dead loads (self-weight + cladding), and seismic forces to the primary structure. Resist impact loads (wind-borne debris in hurricane zones).
2. Weather protection: Exclude rain, snow, wind, and UV radiation. Manage moisture in all three phases (liquid water, water vapor, ice).
3. Thermal and energy performance: Control heat flow (conduction, convection, radiation), solar gain, air leakage, and condensation. The envelope accounts for 25–50% of total building energy consumption.
4. Aesthetics and identity: The facade is the public face of the building. Material, proportion, texture, color, and transparency define architectural character.

1.1 Performance Metrics