How do I know if my house has permitted development rights?

Check the property's planning history on Cornwall Council's register for conditions removing rights, confirm whether the site is in a Conservation Area, AONB or World Heritage Site, and establish whether the house has already been extended — previous extensions consume the allowance.

Does a flat have permitted development rights?

No. Householder permitted development applies to houses, not flats or maisonettes, so almost any external alteration to a flat needs an application.

Is prior approval the same as permission?

No. It is a lighter-touch notification for specified categories, where the council considers a limited set of matters. It still has to be obtained before work starts.

Should I get a certificate to prove it was lawful?

For anything near the limits, yes — see our guide to lawful development certificates. It removes the argument at resale.

Consent · Cornwall

Permitted development in Cornwall — useful, misunderstood, and frequently unavailable

Permitted development lets you build certain things without a planning application. It is genuinely valuable, and it is also the source of most of the bad advice homeowners receive, because the national limits are quoted without checking whether they still apply to that plot.

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The main household allowances

Rear extensions, side extensions, roof alterations, outbuildings and porches all have their own dimensional limits, measured in specific ways that are easy to misread — depth from the original rear wall, height to the eaves at the boundary, and volume for roof works.

Depth is measured from the original rear wall of the house as first built, not the wall you have now
Materials must be similar in appearance to the existing house
Larger single-storey rear extensions require a prior approval notification to the council
Coverage of the original garden by buildings is capped

Where Cornwall takes the rights away

Article 2(3) designated land — Conservation Areas, AONBs, World Heritage Sites — removes or tightens several of the allowances. Cornwall has a great deal of all three. On top of that, many newer housing estates carry conditions on the original permission that specifically remove permitted development rights.

Check the decision notice, not the internet

The five minutes spent reading the original planning conditions for a property is the single most useful check available. If rights have been removed by condition, no amount of compliance with national limits helps.

Frequently asked

Straight answers.

How do I know if my house has permitted development rights?: Check the property's planning history on Cornwall Council's register for conditions removing rights, confirm whether the site is in a Conservation Area, AONB or World Heritage Site, and establish whether the house has already been extended — previous extensions consume the allowance.
Does a flat have permitted development rights?: No. Householder permitted development applies to houses, not flats or maisonettes, so almost any external alteration to a flat needs an application.
Is prior approval the same as permission?: No. It is a lighter-touch notification for specified categories, where the council considers a limited set of matters. It still has to be obtained before work starts.
Should I get a certificate to prove it was lawful?: For anything near the limits, yes — see our guide to lawful development certificates. It removes the argument at resale.

Want to know what you can build without permission?

Send us the address. We will check the designations and conditions and tell you straight.

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