A plain English explanation of this ACT planning and property term.
ACT Missing Middle Housing Design Guide (NI2026-312), Part 3.5 - Building Envelope - https://www.deckquotes.com.au/download_files/ACT_Missing_Middle_Housing_Design_Guide.html
The building envelope is the allowable volume for development rather than the proposed building itself. A design can be smaller than the envelope, and fitting inside it does not by itself prove compliance with every other planning outcome.