Do I Need Planning Permission?
Use the Planning Decision Engine to sense-check the route for a home project before you spend money on drawings, applications or contractor quotes. It weighs the project type, property type, scale and local constraints, then points you to the most useful next page.
Run The Planning Decision Engine
Work through the steps, review the answers, then let the tool check the most common planning triggers for your project.
What This Tool Is Good For
What it answers well
It gives a practical first steer on whether a project still looks comfortably inside the simpler route or whether planning permission is becoming more likely.
What usually changes the answer
Property type, local designations, previous additions and measurements close to a threshold are the factors most likely to move the result.
What to do with the result
Treat the answer as structured triage, then open the matching project guide, planning topic or local authority page before you rely on it.
Questions This Tool Is Best At Narrowing
- Do I need planning permission for this project?
- Could this still be permitted development?
- Is this a borderline scheme worth checking formally?
- Could local constraints change the normal answer?
How This Tool Fits Into The Wider Planning Process
Do I Need Planning Permission? is intended as a quick planning aid based on common UK planning considerations and permitted development limits.
Use it to narrow the question, then move into project guides, local authority pages or formal confirmation if the scheme is close to a limit. The route can differ by country, especially once Scotland or Wales are involved.
FAQ Pages Worth Opening After The Tool
Planning Permission Vs Permitted Development
Read this when the route still sits between the simpler householder answer and a formal application.
Read answerLawful Development Certificate Vs Planning Permission
Useful when the route looks simpler on paper but formal written proof may still be worth it.
Read answerDo I Need Planning Permission?
Read the broader route guide if you want the same decision explained in plainer language.
Read answerDetailed Guidance Worth Opening Next
Planning Permission
Open this when the engine points toward a formal route or a borderline answer.
Open guidePermitted Development
Use this to understand the baseline rights the engine is checking against.
Open guideHouse Extensions
Helpful when the project is an extension and the dimensions are driving the uncertainty.
Open guideLoft Conversions
A strong next read for roof changes, dormers and loft enlargements.
Open guideOutbuildings
Use this for garden rooms, sheds and other detached buildings in the garden.
Open guideLocal Authorities
Best when conservation areas, Article 4 or heritage controls may change the normal answer.
Open guideUse These Tools Properly
What they are for
- Reducing uncertainty at the start of the process.
- Helping you pick the right next page quickly.
- Spotting when the answer probably needs escalation.
What they do not replace
- Formal confirmation for borderline schemes.
- Local authority checks where special controls apply.
- Country-specific checking where England, Wales or Scotland follow different planning routes.
- Detailed professional advice for complex cases.