What planning rules in Lewisham catch homeowners out?

Planning in Lewisham looks straightforward until it isn't. Most homeowners assume a quick Google search will tell them whether they need permission — but the rules that actually matter depend on your specific address, and sometimes even which side of the street you're on. Before you book a builder, it's worth knowing what constraints apply to your exact property in Lewisham — free, takes about a minute.

Conservation areas aren't all the same

Lewisham has conservation areas in Blackheath, Telegraph Hill, Brockley, Lee Manor, and Forest Hill — but knowing you're in one is only the start. The rules aren't uniform across all of them. What's permitted in one may trigger a full application in another. The type of project, the materials, the design, the scale — all of it gets assessed differently depending on which conservation area you're in and what character it's trying to protect.

Most homeowners in SE4 or SE23 have a rough idea they're in a conservation area. Far fewer know exactly what that means for the specific work they're planning.

Article 4 Directions — the rule most people have never heard of

This is where Lewisham catches people out most often. In several of the borough's Victorian conservation areas, Article 4 Directions have been applied specifically to window and door alterations. That means changes you'd assume are minor — swapping out windows, replacing a front door — can require a full planning application even when the same work would be completely fine a few streets away.

Most homeowners don't realise Article 4 Directions exist until after the work is done. At that point, you're looking at retrospective applications, enforcement risk, and a £548 fee you weren't expecting. The best way to avoid that is to check whether an Article 4 Direction affects your specific address before you commit to anything.

Flood zones add a layer most people miss

Properties near the Ravensbourne and Quaggy rivers — running through parts of SE6, SE12, and SE13 — sit in flood zones that restrict what you can build in your garden. Outbuildings, extensions towards the rear, anything that could affect drainage or flow — all of it gets assessed differently for riverside properties. This affects more homes than people expect, and it's not something you'd necessarily know just by looking at your garden.

The north-south divide within the borough

Lewisham is a borough of two characters. The denser inner-city streets in the north — SE8, SE14 — have a very different planning profile to the more suburban south. That affects everything from how applications are assessed to what local precedent looks like. A project that sailed through in Catford might face more scrutiny in Deptford.

The hard question isn't whether rules apply — it's what they mean for your odds

Knowing you're in a conservation area, or near a flood zone, or on a street with an Article 4 Direction is one thing. Understanding what that combination actually means for your specific project — whether similar proposals nearby got approved or refused, and why — is something else entirely. WhatCanIBuild pulls together the approval record for your area so you can see what projects like yours have actually achieved on your street, no signup needed.