TOOL 02 · PLANNING

Will my extension need planning permission?

Name: Vision + Design
Price range: ££

Answer a short set of questions about your property and its constraints for an indicative read on your consent route, the risks that will shape the application, and what to do next. Free, and no email required.

Planning Feasibility Assessment

Answer a few quick questions for an indicative read on your planning route before a formal review.

Project basics

Local authorityYour council sets local planning rules and holds records of conservation areas, Article 4 directions and protected trees. Project typeWhat you're planning to build or change. Conservation areaAn area protected for its character or historic interest, where extra planning controls apply. Check with your councilListed buildingA building legally protected for its special architectural or historic interest. Check the National Heritage List

Site constraints

Article 4 directionA rule some councils apply to a street or area that removes normal permitted development rights, so work usually allowed needs a planning application. Check with your councilTrees or TPO presentA Tree Preservation Order protects specific trees; you need consent to work on or near them. Check with your councilFlood zoneHow likely your site is to flood, which affects what you can build and the reports you'll need. Check the flood risk for your postcodeBasement or subterranean worksDigging down or extending below ground; many London boroughs assess this under specific basement policies and usually require extra reports. Highways or parking impactWhether the work affects access, the road or parking, for example a new dropped kerb or losing a parking space. Likely overlooking or daylight impactWhether the work could look into, overshadow or block light to a neighbour's property, a common reason for objections.

Indicative guidance only, not formal planning advice. Project-specific review is always recommended. Rules current as at Q3 2026.

02 · WHAT THE ASSESSMENT TESTS

Route first, design second.

Four things decide the consent route before any drawing is made: what you are building, whether the property is listed, whether it sits in a conservation area, and whether an Article 4 direction applies to your street. Any one of the last three can remove permitted development rights entirely, whatever the dimensions of your proposal.

The assessment then flags the constraints that add risk rather than remove rights: flood zone, protected trees, basement works, highways and parking impact, and likely overlooking of neighbours. None of these stops a scheme. Each one changes what the application has to answer, and how long it takes.

This is indicative guidance, not formal planning advice. Where an answer is unsure, the result says so rather than guessing, because a designation confirmed late is the most expensive kind of surprise: it means a redesign after the scheme has been drawn to limits that were never available.

Book a consultation.

Thirty minutes with a registered architect to confirm your route, what the site will take, and a fixed fee for the feasibility study.

Book a consultation