Planning approval in Lewisham isn't a coin flip — but it's not a sure thing either. The answer to "how likely is my application to succeed?" almost always comes back to the same frustrating truth: it depends on your property. Tools like WhatCanIBuild exist precisely because that answer looks different for every address in SE4, SE6, SE8, and beyond.
The short version
- Approval odds in Lewisham vary significantly by property, street, and project type
- Lewisham has over 25 conservation areas, and Article 4 directions affect certain streets without most homeowners realising
- What got approved next door may not get approved for you — and vice versa
The borough-wide picture only tells you so much
Lewisham processes hundreds of householder applications every year. Many are approved. But averages are misleading. A high borough-wide approval rate doesn't tell you what happens to applications like yours, on streets like yours, with the specific constraints that apply to your address.
Most homeowners assume that if their neighbour got permission for a rear extension, they will too. That's not always how it works. Subtle differences — which side of a boundary you're on, how your plot sits relative to a protected area, what's happened on your street in the last five years — can shift the outcome entirely.
Conservation areas and Article 4 directions change everything
Lewisham has over 25 conservation areas. If your property falls within one, the rules around what you can do — and how your application is assessed — are different. But here's what most homeowners don't realise: being in a conservation area isn't a binary thing. What it means for your specific project depends on the character of the area, what's been approved nearby, and how the council has interpreted similar cases.
Article 4 directions add another layer. These remove permitted development rights from specific areas — and Lewisham has them in place around parts of Blackheath and Ladywell, among others. You might be assuming your project doesn't need planning permission at all, when actually, on your street, it does.
Worth knowing
Conservation area boundaries and Article 4 directions don't always follow obvious geographical lines. Your neighbour could be inside one while you're outside — or the other way around. Checking your address specifically is the only way to know for certain.
Past decisions on your street are more relevant than you think
Lewisham's planning committee doesn't assess applications in isolation. What's been approved and refused nearby — and the reasons given — shapes how similar applications are treated. A run of refusals for a particular extension type on your road is a signal. So is a cluster of approvals.
But that decision history is buried in planning records most homeowners never look at. And even when you find it, interpreting what it means for your project requires knowing why those decisions went the way they did — not just that they did.
This is where WhatCanIBuild goes beyond what a council planning portal can tell you. It surfaces what's actually been approved and refused near your address, for projects like yours, and translates that into a realistic picture of your approval odds — not just a list of constraints.
Your specific combination of factors is what matters
Flood zones. Listed building status. Local heritage designations. Proximity to protected trees. Each of these can affect your application — and most properties sit at the intersection of several factors at once. Knowing you're in a conservation area is one thing. Knowing what that actually means for a single-storey rear extension on your specific plot, given what the council has approved on comparable properties, is something else entirely.
WhatCanIBuild gives you that second level of insight — the part that the article deliberately can't, because it only exists at the address level.
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