The extension looks great in the listing photos. But did it have planning permission? Is a block of flats about to go up behind the garden? Checking a house's planning history before you buy takes minutes, and it can save you from a nasty surprise after completion.
This guide shows you what to check, where to find it and what the warning signs look like.
Why the planning history matters
When you buy a house, you inherit its planning problems. If an extension, a loft conversion or a change of use was done without the right permission, the council can still take action against the new owner.
The neighbourhood matters just as much. Approved homes on the field opposite, a new road or a solar farm a mile away all change what you are buying.
Step 1: look up the property itself
Search the address on Planning Signal or on the council's planning register. List every application for the house and check:
- Each extension or conversion has a matching approval. Compare the decision with what you can see on site.
- The approved plans match what was built. A rear extension approved at 3 metres but built at 6 is a problem.
- Refusals: a refused application tells you what the council won't accept, which matters if you plan to extend.
- Lawful development certificates: these confirm that existing work or a use is lawful.
Step 2: read the conditions
Approvals come with conditions, and some last forever. Look for conditions that:
- remove permitted development rights, so you need full planning permission for even small changes
- keep a garage as a garage, or stop an annexe being let separately
- require obscure glazing or restrict the use of a roof terrace
A broken condition is a breach of planning control, even if the work itself was approved. Our guide to planning conditions explains what each type means.
Step 3: check for protections on the property
- Listed building: works inside and out may need listed building consent, and unauthorised works are a criminal offence.
- Conservation area: tighter rules on extensions, demolition and trees.
- Article 4 direction: the council has removed some permitted development rights for the whole area.
- Tree preservation orders: you need consent to cut or remove protected trees.
Step 4: look at the neighbourhood
Search a radius around the address and look for:
- new housing approved or pending nearby
- extensions next door that will overlook the garden
- commercial schemes such as takeaways, warehouses or telecoms masts
- national infrastructure projects such as solar farms, power lines, roads and reservoirs
A pending application is the one to watch. It could be approved after you exchange.
Step 5: check the enforcement position
Ask the seller about any enforcement notices, and ask your solicitor to confirm. The local authority search will show formal notices.
Time limits matter. In England, for breaches that happened on or after 25 April 2024, the council generally has 10 years to take enforcement action. Some older work still falls under the earlier 4-year rule for building works and changes of use to a single home. If something was built without permission, don't assume it is safe because it looks old.
Step 6: hand your findings to your solicitor
Your conveyancer runs a local authority search and raises enquiries with the seller. Give them what you found. Specific questions get specific answers, such as "the 2019 extension was approved at 3 metres, but it measures 5".
Missing paperwork is sometimes covered with indemnity insurance. That protects you against the council's costs, but it does not make the work lawful, and contacting the council can void some policies. Take your solicitor's advice before you do.
Get the whole picture in one report
The Signal Report puts every application on record for the address on one page, with what the council approved and refused on the street around it, the constraints that protect the plot and what nearby homes sold for. See a sample report before you buy.
To keep watching after you move in, set up free planning alerts for your new street.
Frequently asked questions
How do I find the planning history of a house?
Search the address on Planning Signal or on the council's online planning register. Older records may only be available by asking the council.
Is it the buyer's problem if work was done without planning permission?
Yes. Planning enforcement runs with the land, so the council can act against the current owner, whoever did the work.
Does a building regulations certificate prove planning permission?
No. Building regulations and planning permission are separate. A house needs both for most extensions, and a completion certificate proves only the building regulations side.
Will my solicitor check the planning history?
Your solicitor will run searches and ask the seller questions, but searches don't always show what was built against the approved plans. Checking the history yourself lets you ask the right questions.