Do I Need Planning Permission for a Home Extension?
It’s one of the first questions homeowners ask — do I need planning permission?
Whether you’re planning a rear extension in West London or a side return in Buckinghamshire, understanding the rules around planning permission can save you time, stress, and money.
Let’s clear it up.
️ What is Planning Permission?
Planning permission is official approval from your local council to carry out certain types of building work. It’s designed to ensure developments are safe, suitable for the area, and respectful of your neighbours and environment.
But not all home extensions require it…
Permitted Development (PD) — What You Can Build Without Permission
Some types of home extensions fall under permitted development rights, meaning they don’t require a formal planning application.
✅ Single-storey rear extensions within 3m (terraced/semi) or 4m (detached)
✅ Side extensions under half the width of the original house
✅ No front-facing changes or major alterations to the street appearance
✅ Max height of 4m (single storey), eaves no higher than the existing house
✅ Materials should match the original house where possible
Always check that PD rights haven’t been removed for your home — this can happen in conservation areas, flats, or new builds.
⚠️ When You DO Need Planning Permission
Building beyond PD limits (e.g., two-storey extensions, exceeding size rules)
Homes in conservation areas, national parks, or areas of outstanding natural beauty
Listed buildings
Changing the front elevation of the property
Building close to a boundary or neighbour’s wall
Even if you fall under PD, you may still want a Lawful Development Certificate (LDC) from the council — it’s useful when selling or remortgaging.
What About Building Regulations?
Planning permission is about how the building looks and fits the local area.
️ Building regulations are about how it’s built (safety, structure, energy efficiency).
✅ Most extensions need to follow building regulations, even if you don’t need planning permission.
This covers:
- Foundations & structure
- Insulation & ventilation
- Drainage & electrics
- Fire safety
West London & Buckinghamshire: Local Considerations
Each council has its own policies and processes. For example:
️ Ealing, Hounslow, Hillingdon may have stricter rules for character homes
️ Buckinghamshire areas like Chiltern or South Bucks may have design codes or green belt zones
Convert Extend will help check your postcode and property history before you build.
️ Why Choose Convert Extend?
We don’t just build — we navigate the system for you.
✔️ Planning checks & advice
✔️ Drawings for applications & LDCs
✔️ Full submission support
✔️ Stress-free approvals
Whether your project needs permission or not, we’ll make sure it’s compliant and smooth.
