Navigating the planning permission landscape in London can feel like a maze. With 33 different local planning authorities—each with its own local plan, housing targets, and supplementary planning documents (SPDs)—what gets approved in Croydon might be flatly rejected in Camden.
Whether you are looking to build a wrap-around rear extension, convert your loft, or create a basement, understanding how the system works in 2026 is your first step to a successful build.
These are the common features that keep a project on the simpler route.
These are the usual triggers that push a scheme beyond straightforward PD rights.
The tool is designed to answer the first question most homeowners have: is this worth pursuing, and what is most likely to block it?
Address-Level Constraints: We check whether your property is in a Conservation Area, is Listed, sits in a Flood Zone, or is affected by an Article 4 Direction — the designations most likely to remove or restrict your Permitted Development rights.
Nearby Planning Precedent: We pull real approved and refused planning applications close to your address, so you can see what the council has actually accepted on comparable streets before you commit to a design.
Permitted Development Eligibility: Based on your property type and the constraints at your address, we assess whether your project is likely to fall within PD rights — or whether a full planning application will be needed.
You need formal planning permission if your project involves building something entirely new, making a major change that exceeds Permitted Development rights, or changing the primary use of your building. If you live in a Conservation Area, a Listed Building, or an Article 4 Direction area, even minor changes like replacing windows might require a full application.
Decisions are based on tiers of policy: the government's NPPF, the Mayor's London Plan, your specific borough's Local Plan, and hyper-local Neighbourhood Plans or SPDs. Officers also consider 'material considerations' such as loss of light (overshadowing) to neighbours, privacy (overlooking), parking, and environmental impact.
Hiring an architect to draft expensive, detailed plans before assessing the actual feasibility of the site. To de-risk: check your constraints, look at precedents from nearby approved schemes, and use a pre-application advice service before committing to a full application.
Use CanUBuild to immediately identify if your home is in a Conservation Area, Flood Zone, or affected by Article 4 Directions, and check for similar nearby approvals before you design.
Search for the address, choose your project type, and get a planning feasibility answer based on permitted development rules, constraints, and local precedent data.