Guides & Insights
Planning Permission
When you need it, when you don't, and how to get it approved.
Guides & Insights
When you need it, when you don't, and how to get it approved.
Planning Permission 101
Planning permission is how the UK controls what you can build, demolish or change about a property. Most architectural projects need it — but not all. This guide explains when you need it, how the process works, and how to maximise your chances of approval.
The rules are set nationally (via the National Planning Policy Framework) but decisions are made locally by your council. This creates significant variation — something that would be approved in Wandsworth might be refused in Richmond.
We regularly handle planning applications across the Isle of Wight, London, Hampshire and beyond. Below is what we've learned.
Discuss Your ProjectThe First Question
The short answer: it depends on what, where and how big. Some works fall under permitted development rights (no planning needed); others need full planning permission.
Important: permitted development rights are often restricted or removed by Article 4 directions (common in conservation areas), by conditions on the original planning consent, or because the property is in an AONB, National Park or covered by covenants.
The safest way is to apply for a Lawful Development Certificate (LDC). For a fee of around £130, the planning authority confirms in writing that your proposal falls under PD rights. This gives legal certainty — worth doing for any project at the edge of PD limits.
Permitted Development Key Limits
| Work Type | PD Limit (detached house) | PD Limit (semi/terrace) |
|---|---|---|
| Single-storey rear extension | Up to 8m depth | Up to 6m depth |
| Single-storey side extension | Half width of house, max 4m height | Half width of house, max 4m height |
| Loft conversion | 50m³ added volume | 40m³ added volume |
| Outbuildings | Up to 50% garden area, max 2.5m height (or 4m with pitched roof) | Same |
| Porch | Up to 3m², 3m height, >2m from highway | Same |
These limits are simplified summaries. Full PD rights are governed by the General Permitted Development Order (GPDO) 2015 as amended. Article 4 directions, conservation areas, AONBs and National Parks restrict these rights.
The Process
A typical householder application takes 3–4 months from starting to decision.
Paid consultation with the planning authority. Written feedback on your proposal before committing. Typically 4–8 weeks.
Drawings, Design & Access Statement, supporting documents. Your architect coordinates consultants (ecologist, heritage, etc.) as needed.
Online via the Planning Portal. Application fee typically £258 for a house extension (2025 rate).
Neighbours and statutory consultees (highways, environment agency) have 21 days to comment. Case officer reviews objections and policy implications.
Householder applications decided in 8 weeks by law; larger applications in 13 weeks. Decision either approved, approved with conditions, or refused.
Special Designations
If your property sits within any of these, the rules are significantly tighter.
01
Designated areas of special historic or architectural interest. Many permitted development rights are removed. Extensions must respect the character of the area. Conservation Area Consent needed for demolitions.
02
Development is tightly controlled to protect landscape character. New houses usually only approved as replacement dwellings or under Paragraph 80 exceptional design. Extensions are scaled to the original building.
03
Every alteration — internal or external — requires Listed Building Consent on top of planning permission. Grade I and II* buildings also need Historic England approval. See our Listed Building Guide.
04
Local directions that remove specific permitted development rights in defined areas. Common in conservation areas — e.g. removing the right to install UPVC windows or solar panels on the front elevation.
If Your Application Is Refused
Revise and resubmit. Read the decision notice carefully — the reasons for refusal are listed. Many refusals can be addressed through design amendments and a fresh application. There's no fee for the first resubmission within 12 months.
Negotiate with the case officer. If the reasons for refusal feel minor, ask the officer what amendments would make the scheme approvable. Most officers prefer to approve an amended scheme than have to refuse a revised one.
Appeal to the Planning Inspectorate. Free to submit, but takes 6–18 months. Appeals are decided by an independent Planning Inspector. Allowed where you believe the council's decision is wrong in planning terms.
Accept the decision. Sometimes a refusal reflects a fundamental planning objection that can't be designed around. In that case the honest answer is to find a different approach — or a different site.
Ready to Apply?
Pre-application strategy, full applications, listed building consent, appeals. Across the Isle of Wight, London, Hampshire and beyond.
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