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 People Usually Ask After The Result
Keep this block for the interpretation and trust questions that usually appear once the tool has narrowed the answer.
Is do i need planning permission? a final answer?
No. Do I Need Planning Permission? is built to narrow the planning question quickly, not to replace the project guide, local authority layer or formal verification where certainty matters.
What details most often change the result?
Property type, exact measurements, previous additions, flats, listed buildings, conservation areas and Article 4 are the factors most likely to move the result.
When should I verify formally?
Stop relying on the tool alone once the route only works inside a tight threshold or the cost of being wrong is meaningful.
What page should I open next?
Open the project guide or rule page the result has just isolated, then go local if the answer still depends on council-specific controls.
Why does local context still matter after the tool?
Because conservation areas, listed buildings, Article 4, planning history and council-specific judgement can still make a familiar-looking result less reliable on a real site.
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 fast planning triage step 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 tool should help you spend money in the right order, not tempt you to stop checking too early.
Need A More Tailored Steer Than The Tool Result?
If do i need planning permission? has narrowed the question but the answer still depends on your exact site, local authority area or project details, use the structured guidance form instead of relying on another broad rule of thumb.
Best for
Borderline, awkward or site-specific cases where broad guidance has helped, but the answer still turns on facts that are unique to your property or proposal.
What the reply aims to do
The reply aims to narrow the likely route, flag the tripwires that matter most, and tell you which verification step is safest before more money is spent.
What to include
Property type, council area, location, the change you want to make, approximate dimensions, relevant heritage or flat-related details, previous additions and the main concern.
Important: Replies are informational personalised guidance based on the details you provide and publicly available information. They are not formal legal, architectural, surveying or council advice. Site-specific or borderline cases may still need checking with the local authority or a qualified specialist before drawings, applications or contractor spend move ahead.
Your enquiry details are used to respond to your request. Anonymised themes may be used to improve guides, tools, FAQs and site content. Identifiable case details are not published without permission, and sending an enquiry does not sign you up to marketing emails. Privacy notice.
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
Rules vary by location
Planning routes can change by council area, property history, designations and the exact proposal. Use this page as a structured guide to the next check, not as a blanket approval.
What this page is for
To reduce uncertainty quickly, point you to the next page that matters, and show when a broad tool result is still too weak to rely on for a live project decision.
What it does not replace
These tools do not replace formal confirmation for borderline schemes, local authority checking where special controls apply, or paid specialist input for genuinely complex cases.
How the guidance is built
Tool results are based on common planning and permitted development baselines, then framed to push you toward the project, local authority and rule pages most likely to settle the remaining doubt.
When to stop relying on broad guidance
Escalate when the route only works inside a tight threshold, when local controls may be doing most of the work, or when you need written certainty before drawings, applications or contractor spend.
Safest formal next step
Use the tool result as triage, then move into the matching guide. If certainty still matters, step up to a lawful development certificate, pre-application advice or professional help rather than rerunning broad checks.
Official-source check
Where this page shows official sources, use those links near the relevant answer to confirm the latest council or national wording before relying on a borderline route.