How to search planning history before buying a property

Planning history is one of the most overlooked parts of pre-offer research, and one of the most revealing. It tells you what has happened to a property in the past — whether extensions were ever built without consent, whether there are live applications that could change the street — and what might be coming next. Here's how to research it effectively.

What planning history covers

Planning applications are public records, maintained by each local planning authority (LPA) and now aggregated nationally at planning.data.gov.uk. Every application for the property itself — and for land and buildings nearby — is listed with its date, description, status (approved, refused, withdrawn, pending), and decision documents.

You're looking for three things:

1. Unauthorised works on the property itself — extensions, outbuildings, or conversions built without planning permission that required it
2. Live applications that could affect the area — new residential developments, commercial units, roads, or infrastructure nearby
3. Refused applications — a string of refused applications nearby can indicate planning policy constraints that might affect your own future improvement plans

How to check if a property has unauthorised works

Compare the current building against the planning record. If there's an extension, loft conversion, or outbuilding that has no corresponding planning application or permitted development notification, it may have been built without consent.

This matters because:

• Unauthorised works can complicate your mortgage — some lenders require a certificate of lawful development before lending
• If the LPA issued an enforcement notice, the obligation to remedy it may pass to new owners
• It can affect buildings insurance and Buildings Regulations compliance

The usual remedy is indemnity insurance (available for most cases where the works are older than 4 years and enforcement is unlikely) — but it's better to know upfront and negotiate the cost of the policy into the purchase.

Checking for nearby development

Search a radius of around 400 metres for any live or recently approved applications. Look specifically for:

• Residential development — a new block of flats or estate can affect views, parking, road noise, and even the feel of the neighbourhood
• Commercial or industrial use — a depot, takeaway, or nightclub changing the character of the area
• Infrastructure — road schemes, pylons, substations
• Prior approval applications — offices converting to flats under permitted development rights; these can appear with very little warning and no traditional planning process

Approved doesn't mean built — check the decision date and any conditions. Many approved applications lapse after 3 years if not implemented. But a permission granted recently is real risk.

The national planning register

The national open-data planning register at planning.data.gov.uk aggregates data from local authorities across England and makes it searchable by location. It's the most efficient way to get a national picture without visiting 300+ individual council planning portals. Coverage is improving but still has gaps for some councils.

For the council's own detailed decision notices, reports and drawings, you'll need to visit the individual LPA planning portal — which you can find via your council's website.

Planning constraints on the property itself

Separate from applications, there may be constraints that limit what you can do with the property in future:

• Listed building status — you need Listed Building Consent for almost any alteration, internal or external, and work without it is a criminal offence
• Conservation area — permitted development rights are significantly reduced; even replacing windows requires consent in most cases
• Article 4 direction — a local planning authority can remove permitted development rights from an area, requiring planning permission for works that would normally be exempt
• Tree preservation orders (TPOs) — trees on the plot may not be pruned or felled without LPA consent

Putting it all together

Planning research takes time if done manually across multiple portals. A Property Snapshot report pulls planning application history for any property through the national planning register, flags listed building status, and presents it alongside the property's full data profile — so you can see planning history in context alongside flood risk, sold prices, schools and everything else, in one document.