Borough-level guidance is helpful, but planning outcomes are decided at address level. The fastest way to get the right answer is to combine the project details (size, height, storeys) with local constraints and nearby precedent decisions.
This page explains the usual rules, the common reasons permitted development does not apply, and how to check your exact property in City of London before you pay for drawings.
Common projects that may be straightforward when they fit within PD limits and local constraints.
These are the usual reasons planning permission becomes more likely in City of London.
The biggest drivers of approval are the exact proposal (dimensions and design) and the exact site constraints (designation, conditions, neighbour impacts). Use borough context as a starting point, then validate it with address-level checks and nearby precedents.
Projects that stay modest in size, match materials, and avoid obvious neighbour impacts are more likely to be straightforward — even before you consider borough-specific policies.
Conservation areas, listed buildings, Article 4 directions, flood risk and TPOs can flip the answer. Address-level checks stop you wasting money on the wrong scheme.
The fastest signal is what the council has approved or refused on comparable streets nearby. Precedent does not guarantee success, but it helps you shape a lower-risk design.
Councils rarely refuse the “idea” of an extension or loft conversion — refusals are usually about scale, design, neighbour impacts, and policy/designation conflicts. When you run a check, CanUBuild shows nearby approvals and refusals so you can see what has worked locally.
Search the address, choose your project type, and get an answer based on permitted development rules, local constraints, and nearby precedent decisions.
Sometimes. Many straightforward house extensions can fall under permitted development, but the answer depends on the exact size, design, the type of property, and whether local constraints apply to your address.
Conservation area controls, listed building status, Article 4 directions, planning conditions on earlier permissions, and flats/maisonettes are common reasons PD rights do not apply in the usual way.
Some loft conversions can be permitted development, but dormers, roof changes, front-facing alterations, and constraints on the property can push the project into full planning permission territory.
Use the CanUBuild checker to search for your address, select your project type, and see address-level constraints plus nearby precedent approvals/refusals for context before you spend money on drawings.