What Can You Do Under Permitted Development? A Simple Guide
As a homeowner looking to extend your property, one of the first things you’ll want to understand is whether you need full planning permission or if your project falls under permitted development (PD).
Permitted development allows certain types of extensions and alterations without the need for a full planning application, saving time, cost, and complexity.
But what can you actually do with a rear, side, or loft extension under permitted development? Here’s a clear breakdown.
1. Rear Extensions Under Permitted Development
Rear extensions are one of the most common and straightforward types of extension under permitted development.
What’s Possible
- Size: Up to 3 metres in depth for terraced or semi-detached homes, or 4 metres for detached homes
- Height: Maximum height of 4 metres
- Roof type: Flat or modest pitched roofs are typically acceptable
- Position: Must not extend beyond the original rear wall of the property
What You Can’t Do
- Extend beyond the side of the property under rear extension rules
- Exceed the size or height limits
- Ignore location restrictions such as Conservation Areas or protected land
2. Side Extensions Under Permitted Development
Side extensions are possible under permitted development but come with stricter limitations.
What’s Possible
- Width: Must not exceed half the width of the original house
- Position: Cannot extend beyond the front elevation
- Height: Maximum of 4 metres for single-storey extensions
- Boundaries: Should not be within 1 metre of the boundary if it impacts neighbours
What You Can’t Do
- Build a two-storey side extension under permitted development
- Extend to the side in restricted areas such as Conservation Areas, National Parks, or protected landscapes
3. Loft Extensions Under Permitted Development
Loft conversions are a popular way to add space without extending outward, and many can be completed under permitted development rules.
What’s Possible
- Volume: Up to 40m³ for terraced houses and 50m³ for semi-detached or detached homes
- Roof alterations: Adjustments to improve head height are often allowed
- Dormers: Rear dormer extensions are usually permitted within limits
What You Can’t Do
- Add dormers to the front or side elevations without planning permission
- Exceed the permitted volume limits
- Carry out loft work under permitted development in restricted properties
4. Important Considerations for All Extensions
Even when your project falls under permitted development, there are still key factors to consider.
- Neighbours: While permission isn’t always required, keeping neighbours informed can prevent issues
- Building Regulations: All extensions must comply with structural, safety, insulation, and drainage requirements
- Property restrictions: Conservation Areas, Listed Buildings, and Article 4 Directions may limit or remove permitted development rights
5. How Plan It UK Can Help
Permitted development rules can be more complex than they first appear. Understanding what applies to your specific property is key to avoiding delays or costly mistakes.
At Plan It UK, we help you assess whether your project qualifies under permitted development, design a compliant extension, and guide you through the full process from concept to construction.
Planning an Extension?
If you’re considering a rear, side, or loft extension, we’re here to help you make the most of your space while staying fully compliant.
Get in touch or book your free consultation today to discuss your project.
