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London Conservation Areas: Building Work Guide

What you need to know about planning constraints and design when working in a London conservation area.

Planning GuideApril 2026Conservation
Overview

Building work in conservation areas

London has over 1,000 conservation areas with restrictions. Pre-application advice clarifies the position before you commit to a design.

Permitted development restrictions

PD rights are more limited in conservation areas. Side extensions, cladding, satellite dishes and some roof alterations require full planning permission. Article 4 directions remove additional rights.

Design and materials

Planning authorities expect new work to respect the area's character. An experienced architect can design proposals satisfying both the planning authority and client's brief.

Planning applications

Applications are assessed against the duty to preserve or enhance the area's character. Well-prepared applications with heritage impact assessments have better approval prospects.

Listed buildings

Many conservation areas contain listed buildings with additional protections requiring listed building consent for works affecting character.

FAQ

Frequently asked questions

Do I need planning permission in a conservation area?

Many works normally permitted require planning permission in conservation areas, including side extensions, cladding and some roof alterations.

What materials should I use?

The planning authority expects materials respecting the area's character. Traditional materials matching the existing building are usually preferred.

How long does a conservation area application take?

Typically eight to thirteen weeks. Well-prepared applications with pre-application engagement have better prospects.

Can I replace windows in a conservation area?

Like-for-like is usually acceptable. Changing style, material or configuration often requires permission. uPVC may be refused in favour of timber.

Next Steps

How we can help