What planning rules in Cornwall catch homeowners out?

Cornwall is one of the most planning-restricted counties in England — and most homeowners only discover that after they've already started work. With 145 conservation areas, over 5,000 listed buildings, and multiple designated landscapes cutting across the county, the rules that apply to your property can be completely different from those that apply to your neighbour. WhatCanIBuild exists precisely because that complexity is nearly impossible to untangle without checking your specific address.

Conservation areas cover more of Cornwall than most people realise

With 145 conservation areas spread across the county — from Truro's city centre to small fishing villages along the coast — the chances that your street falls within one are higher than in most English counties. Most homeowners don't realise that being inside a conservation area doesn't just restrict dramatic changes. Relatively modest external alterations, things you'd assume were fine, can suddenly require planning permission. And the rules aren't uniform across every conservation area — what applies in one part of Cornwall may not apply in another. Do you know which side of the boundary your property sits on?

AONBs, the World Heritage Site, and Article 1(5) land

Cornwall borders or partially overlaps the Cornwall AONB, the North Devon AONB, and the Tamar Valley AONB. It also contains the Cornwall and West Devon Mining Landscape World Heritage Site. Properties near or within those boundaries are classified as Article 1(5) land — a designation that restricts permitted development rights in ways that catch homeowners completely off guard. The problem is that boundary lines don't follow street patterns or postcode areas. A terrace of identical houses can have entirely different planning rules depending on exactly where the line falls. Most homeowners have no idea whether their property is on Article 1(5) land until they check.

Listed buildings: more common than you'd expect

More than 5,000 listed buildings are recorded across Cornwall. That's a significant number for a single county — and listed building status affects far more than structural work. Internal changes, replacement windows, even certain repairs can require listed building consent. If you're not certain whether your property is listed or curtilage-listed (meaning it's affected by a nearby listed building), that uncertainty alone is a reason to check before doing anything.

The rules that actually matter are the ones specific to your property

That's the part no general article can tell you. Knowing Cornwall has conservation areas is useful background. Knowing whether your specific property in TR1, PL26, or EX23 sits inside one — and what that means for the exact project you're planning — is something else entirely. WhatCanIBuild shows you what's been approved and refused for similar projects near your address, what your property's specific combination of constraints actually means for your chances, and whether projects like yours on your street have a track record of going through. That's the difference between knowing the landscape and knowing your position in it.

The best way to find out what applies to your Cornwall property — before you commit to anything — is to check your address directly.