BASIX Ventilation Changes 2026: Why Exhaust-to-Roof-Space Is No Longer an Option for NSW Builders What changed in BASIX ventilation rules in 2026? From 1 May 2026, the BASIX tool (version 4.04) removed the option to direct bathroom, kitchen, and laundry exhaust systems into the roof space. All exh... BASIX NSW Planning Sustainable Building Ventilation basix-compliance energy efficiency Sep 7, 2026