27/08/2026
A summary of the 4 main changes to planning exemptions for home owners:
Habitable Garden Rooms (Class 3A): You can build a detached auxiliary dwelling (e.g., a modular log cabin or garden room for a relative) between 32m² and 45m² in your rear garden without planning permission, provided it connects to the main house's utilities.
Subdivision of Houses (Class 1A):
You can segment an existing house into two separate self-contained units, provided each unit is a minimum of 32m².
Larger Extensions (Class 1):
The baseline cap for a standard, non-previously extended home extension has increased from 40m² to 45m².
Loft & Roof Modifications:
New provisions explicitly exempt specific dormer window extensions to the side or rear, alongside front-facing roof lights.
