Do I need planning permission for an extension?

Many single-storey rear extensions fall under permitted development and don't need planning permission, provided they meet size and height limits. Use PlanWise to check your specific situation instantly.

Is PlanWise free to use?

Yes, PlanWise is completely free. Get instant AI-powered planning permission advice, check property constraints, view planning history, and submit mock applications at no cost.

How accurate is AI planning advice?

PlanWise is built on the National Planning Policy Framework (NPPF), the General Permitted Development Order (GPDO), and official planning data from planning.data.gov.uk. While it provides reliable preliminary guidance, always verify with your Local Planning Authority for formal decisions.

AI-Powered Planning Advice

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Do you need planning permission? Find out in seconds. Describe your project, check your property constraints, and get AI-powered guidance on permitted development, extensions, loft conversions, change of use, and more — without the consultant fees.

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Everything you need to understand planning

Get clear, structured answers to your planning permission questions, all in one place.

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Describe your plans in plain English. Our AI understands the nuances of UK planning law and will guide you accordingly.

Structured Advice

Receive clear, organised responses covering permitted development rights, application requirements, and key considerations.

Up-to-Date Policy

Built on the latest NPPF, General Permitted Development Order, and local planning guidance documents.

Instant Results

No waiting days for a consultant callback. Get preliminary guidance in seconds so you can plan with confidence.

Property-Specific

Provide your property details and get tailored advice that accounts for your specific context and constraints.

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Understand your planning position before engaging expensive professionals. Enter conversations informed and prepared.

Three simple steps

From question to clarity in minutes, not weeks.

Describe Your Project

Tell us about your property and what you are planning. Extensions, conversions, new builds — any type of development.

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Our AI analyses your query against current UK planning policy and provides structured, actionable guidance.

Plan With Confidence

Use your personalised advice to decide next steps — whether to proceed under permitted development or apply for permission.

Powerful tools at your fingertips

Three integrated tools to cover every stage of your planning journey.

Planning Advisor

Ask questions in plain English and get structured, AI-powered guidance on UK planning regulations, permitted development, and application requirements.

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Property Checker

Live Data

Check any property against 13+ planning constraint datasets and view previous planning applications from 425 UK authorities. Conservation areas, listed buildings, flood zones, and more.

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Mock Application

Submit a mock planning application and receive a simulated officer assessment with approval likelihood, policy compliance analysis, conditions, and improvement suggestions.

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What can you ask?

Here are some examples of the questions PlanWise can help with.

Can I build a single-storey rear extension without planning permission?I want to convert my garage into a home office. What are the rules?My property is in a Conservation Area — what additional restrictions apply?Do I need planning permission to install solar panels on my roof?What is the maximum height for a garden fence without permission?I want to build a loft conversion with a rear dormer. What do I need?

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Stop wondering and start planning. Get instant advice on your UK planning permission questions today.

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