Step-by-Step Guide to Planning Permission for House Extensions (2025 UK Guide)

Thinking about extending your home? Whether you're planning a rear extension, side return, or wraparound build, understanding the planning permission process is essential. In this guide, we’ll walk you through every step of obtaining planning permission for a house extension in the UK — and explain when you might not even need it.

✅ Do You Always Need Planning Permission?

Not always. Some extensions fall under Permitted Development Rights (PD) — which allow certain types of work without a full planning application. However, PD rules are strict and don’t apply to:

• Flats or maisonettes

• Homes in conservation areas

• Large or high-impact extensions

• Listed buildings

• Previous homes with PD rights removed (via Article 4 Direction)

If in doubt, speak with your architect or local planning department.

📝 Step-by-Step Planning Permission Process

1. Consult a Qualified Architect or Designer

Before submitting anything, consult with a RIBA-registered architect or architectural technician. They’ll:

• Assess your property and goals

• Advise whether PD applies

• Draw up concept designs

• Ensure plans meet local planning policies and building regulations

💡 At Morphos Group, our in-house design team handles this entire process for you.

2. Check Local Planning Guidelines

Each local authority in the UK may have its own guidance on:

• Roof heights and materials

• Distance from boundaries

• Design compatibility with neighbouring homes

• Impact on light and privacy

You can check this on your local council’s website under “Residential Extensions” or “Planning Policy”.

3. Prepare the Planning Application

If PD doesn't apply, your architect will prepare:

• Existing and proposed drawings

• Site plans and elevations

• Design & Access Statement (in some cases)

• Application forms (via the Planning Portal)

• Application fee (usually £206 for extensions)

4. Submit Through the Planning Portal

Applications in England are submitted through PlanningPortal.co.uk. Once submitted, you’ll receive confirmation and a reference number.

5. Application Review Period (8 Weeks)

The local authority will:

• Consult your neighbours

• Review compliance with national and local policy

• Conduct site visits if needed

• Recommend approval or refusal

This stage typically takes 8 weeks for householder applications. For complex cases or conservation areas, it may take longer.

6. Planning Decision

You’ll receive either:

• ✅ Approval with conditions (you must meet them before starting)

• ❌ Refusal (with reasons and guidance on resubmitting or appealing)

If approved, you’ll usually have 3 years to begin the work.

🏗️ What Happens After Approval?

Once planning is granted:

• You must also get Building Regulations Approval (handled separately)

• A structural engineer may be required for calculations

• You’ll need to notify Building Control before and during construction

• If you share walls, you may also need a Party Wall Agreement

💡 At Morphos Group, we offer full design & build packages — including planning, building regs, and construction.

🚫 What If My Application Is Refused?

You have options:

• Revise and resubmit based on feedback

• Appeal the decision (via the Planning Inspectorate)

• Explore alternative design solutions under PD

We recommend working closely with your architect to avoid refusals before they happen.

🔍 Summary: Planning Permission Checklist

✔ Consult an architect or design & build specialist✔ Confirm if Permitted Development applies✔ Prepare drawings and application materials✔ Submit via the Planning Portal✔ Wait 8 weeks for a decision✔ Secure Building Regs and Party Wall approval✔ Begin construction within 3 years

🧱 Let Morphos Group Handle It for You

At Morphos Group Ltd, we offer end-to-end design and construction services — from initial drawings and planning permission to build and final handover. We manage the paperwork, liaise with your local council, and keep your project on track every step of the way.

📍 Serving London and the South East📧 enquiries@morphosgroup.co.uk📞 020 3916 5641📅 Book a free consultation today