How to Identify Unauthorised Works in a Listed Property Before You Buy

Buying a listed home? Here’s a straightforward guide to spotting unauthorised works before you commit — and how to avoid legal or financial surprises later.

Buying a listed property is exciting, but it can also raise important questions – especially about whether past alterations were carried out legally.

Because Listed Building Consent is required for any work that affects a building’s character, unauthorised changes can create significant risk during a purchase.

Not all issues are apparent. Some are subtle, some are historic, and many sellers are unaware of what required consent in the first place.

Below is a simple, calm guide to identifying potential unauthorised works before you buy — and what to do if you spot them.

Why Unauthorised Works Matter

If past works were carried out without consent, the liability passes to the new owner.

This can lead to:

• enforcement action
• costly remedial works
• delays or complications during future sales
• difficulty obtaining future consents
• in extreme cases, potential legal implications

Most issues are manageable, but the key is identifying them early.

Common Signs of Unauthorised Works

1. Altered Layouts That Don’t Look Original

Many listed homes have been altered over generations, but some changes required consent. Be cautious if you see:

• open-plan ground floors
• large openings between front and rear rooms
• removed chimney breasts
• reconfigured staircases
• newly combined bedrooms

These may be perfectly acceptable – but they must have been approved.

2. Modern Kitchens or Bathrooms in Unusual Locations

Kitchens and bathrooms are flexible spaces, but relocating them often involves:

• drainage
• ventilation
• structural changes

If these facilities appear in unusual or unlikely locations, check whether consent was granted.

3. Contemporary Extensions That Don’t Match Past Records

A rear extension, basement room, or glazed addition should always have:

• planning approval
• Listed Building Consent

If the extension looks relatively recent, yet is absent from the planning history, this is a red flag.

4. New Windows or Doors That Don’t Look Traditional

PVC, thin frames, or modern profiles are rarely acceptable in listed buildings. If you notice:

• double glazing with thick profiles
• modern doors
• non-traditional openings

…these may have been installed without consent.

5. Missing Historic Features

If fireplaces, cornices, panelling, or doors appear to have been recently removed, this may have been unlawful – especially if the building has a known historic plan form.

Where Buyers Often Get Caught Out

A. Works Done “A Long Time Ago”

Even old, unauthorised works can still constitute a breach. There is no “ten-year rule” for listed buildings.

B. Alterations Done by Previous Owners Who “Didn’t Know”

Ignorance is not a defence. Responsibility always transfers to the new owner.

C. Internal Works That “Seem Minor”

Listed Building Consent applies to internal changes, including even small ones.

D. Partial Planning History

Some councils’ online records omit older consents. Cross-checking is essential.

How to Check for Unauthorised Works Before You Buy

1. Review the Planning History

Check:

• Listed Building Consent (LBC)
• householder planning applications
• historic approvals
• enforcement notices

Our pre-purchase service includes a full review of this.

2. Compare the Existing Layout to Historic Plans

Misalignments often reveal where work occurred. We can assess these quickly during due diligence.

3. Identify Features That Look “Out of Place”

A modern staircase in a Georgian home, or a missing chimney breast, merits investigation.

4. Talk to the Vendor (But Don’t Rely on Their Memory)

Many owners genuinely believe their works did not require consent. Everything should still be verified independently.

5. Bring a Heritage Professional In Early

Spotting issues early can prevent:

• unexpected costs
• negotiation breakdowns
• post-purchase enforcement
• complex regularisation procedures

We often identify risks within minutes of reviewing a floor plan and photographs.

What Happens If You Do Find Unauthorised Works?

Don’t panic. Most situations can be resolved with a clear regularisation strategy.

This usually involves:

• assessing the scale of unauthorised works
• determining what can be retained
• preparing heritage justification
• applying for Listed Building Consent retrospectively
• ensuring compliance with Building Regulations

We have successfully regularised complex projects – including those already under investigation.