The new Planning and Development (Exempted Development) Regulations 2026 come into effect from Monday July 27th and represent the biggest expansion of residential planning exemptions in many years. Their aim is to make it easier for homeowners to adapt existing homes, create accommodation for family members and reduce pressure on the planning system.
The main changes include:
- Larger house extensions
The exempted size limit for rear house extensions increases from 40 m² to 45 m², provided the development continues to comply with the other exemption conditions (such as open space, height and other planning rules).
- New exemption for detached garden homes ("granny flats")
One of the most significant changes is a new exemption allowing a detached self-contained auxiliary dwelling within the curtilage of an existing home, without planning permission, subject to detailed conditions.
The conditions include matters such as:
- maximum floor area (up to 45 m²),
- use as an auxiliary dwelling associated with the main house,
- compliance with Building Regulations,
- servicing requirements,
- notification/registration requirements,
- and various siting and access rules.
These units are intended for accommodation such as elderly relatives or adult children, rather than creating a completely independent new residential site.
- Internal subdivision of existing houses
Homeowners can also, in certain circumstances, subdivide an existing dwelling to create one additional self-contained unit within the existing building footprint without planning permission, subject to minimum size and other regulatory conditions.
- Larger exempt garden structures
The exemption for detached garden buildings (such as:
- home offices,
- gyms,
- studios,
- storage sheds)
increases from 25 m² to 30 m².
- Easier attic conversions
New exemptions are introduced for certain attic conversion works, including:
- dormer roof boxes,
- rooflights,
- and associated works,
provided they comply with the detailed dimensional limits in the regulations.
- Front garden improvements
Additional works become exempt, including features such as:
- bicycle storage,
- bin storage,
- and some energy-efficiency improvements like external insulation, subject to the prescribed conditions.
Important caveats
These are planning exemptions only. They do not remove the need to:
- comply with the Building Regulations,
- meet fire safety and drainage requirements,
- satisfy wastewater and utility requirements where applicable,
- comply with any restrictive planning conditions attached to the original house,
- or meet any notification or registration requirements specified in the regulations.
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