Thinking of adding more space to your home in East Sussex? A well-designed house extension is a great way to improve your living environment and increase the value of your property. But before any work begins, it’s essential to understand the rules around planning permission.

At SDS Builders, we’ve helped hundreds of East Sussex homeowners navigate the planning process – from initial design to full build. In this guide, we’ll explain when planning permission is required, what’s covered under permitted development, and how to ensure your project gets approved smoothly.

Do I Need Planning Permission for a House Extension?

The short answer is: not always. Many single-storey and rear extensions fall under permitted development rights, meaning you can build without applying for full planning permission – provided the design meets specific criteria.

However, there are key exceptions and limitations, especially in East Sussex, where some properties are in conservation areas, Areas of Outstanding Natural Beauty (AONB), or are listed buildings.

What Is Permitted Development?

Permitted development allows you to carry out certain types of building work without applying for planning permission. For house extensions, the general permitted development guidelines include:

Single-storey rear extension:

• Up to 3 metres deep for a terraced/semi-detached house
  
• Up to 4 metres deep for a detached house
  
• Must not cover more than 50% of the total land around the house
  
• Must be no higher than 4 metres overall
  

Side extensions:

• Must be single-storey and no more than half the width of the original house
  
• Must not extend beyond the front wall of the property
  
• Maximum height of 4 metres
  

Double-storey extensions:

• Must not extend more than 3 metres from the rear wall
  
• Must be at least 7 metres from the rear boundary
  

These rules apply to the original house as it stood on 1 July 1948 (not including previous extensions).
Note: Permitted development does not apply to flats, maisonettes, or houses in certain designated areas without additional approval.

When Is Full Planning Permission Required?

You’ll need to apply for planning permission if:

• Your extension exceeds the permitted development limits
  
• Your property is listed
  
• You live in a conservation area or AONB (e.g. South Downs National Park)
  
• You want to build two-storey or complex extensions
  
• Your plans involve significant changes to the appearance of your home
  
• You’re planning a wraparound extension or loft conversion with a large dormer
  

We recommend speaking to a local builder or architect early on – mistakes or assumptions here can be costly and delay your project.

Planning Permission Process in East Sussex

If you do need planning permission, here’s how the process usually works:

1. Initial design and site survey – We’ll visit your home and discuss your ideas
   
2. Architectural drawings – Created to scale and in line with local authority requirements
   
3. Planning application submission – Submitted to your local council (e.g. Lewes, Wealden, Rother)
   
4. Consultation period – Usually lasts 8 weeks, during which neighbours and other stakeholders can comment
   
5. Decision – Your council will approve, reject or ask for amendments
   

SDS Builders can manage this entire process on your behalf, working closely with trusted local architects and planning consultants.

Special Considerations in East Sussex

East Sussex has many characterful towns and villages (like Rye, Lewes, Alfriston, and Hastings Old Town) where local planning authorities are particularly protective of historic streetscapes and architectural features.

You may face additional restrictions on:

• Building materials and finishes
  
• Roof shapes, dormers, and extensions visible from the road
  
• Front extensions or alterations in conservation areas
  

We’ll help you design an extension that meets your needs and complies with local planning expectations.

What If My Project Doesn’t Need Planning Permission?

Even if planning permission isn’t required, you may still need to:

• Apply for a Lawful Development Certificate (optional, but useful when selling your home later)
  
• Submit a Building Regulations application for structural, electrical, plumbing, and fire safety compliance
  
• Notify your neighbours under the Party Wall Act, if your work affects shared walls or boundaries
  

At SDS Builders, we ensure all relevant permissions, inspections, and safety measures are fully covered.

Why Choose SDS Builders?

✅ Over 20 years’ experience building extensions across East Sussex
✅ We handle planning, design, and full project management
✅ Local knowledge of councils, including Wealden, Rother, and Eastbourne
✅ Skilled in working with conservation and heritage properties
✅ Trusted by homeowners for our quality, transparency, and service

Whether you’re building a new kitchen extension or adding extra bedrooms, we’ll make the process clear, compliant, and stress-free from day one.

Ready to Plan Your House Extension?

Speak to our team today and get expert advice on planning, design, and costs – with a free, no-obligation quote.

Call now or Request your quote online

FAQs: Planning Permission in East Sussex

Do I need planning permission for a rear extension?
You might not – if it fits within permitted development rules. We’ll assess this during your initial consultation.

What if my property is in a conservation area?
You may need full planning permission. We have experience working with sensitive locations and can guide you through the process.

Can SDS Builders handle the planning application?
Yes – we can manage all planning and building regulation submissions as part of our service.

How long does it take to get planning permission?
Typically around 8 weeks, though more complex applications can take longer.

What happens if I build without planning permission?
You risk enforcement action, fines, or even being asked to reverse the work. It’s always best to check first.