Guide · 7 min read
Planning Permission & Permitted Development: A Homeowner's Guide
When you need planning permission, when permitted development applies, and how party walls and building regulations fit in.
Few subjects cause more anxiety at the start of a project than planning. The good news: for most home improvements the rules are well trodden, and the right route is usually clear within one conversation. This guide covers the essentials for homeowners in London and the Home Counties.
Planning permission vs permitted development
Planning permission is formal consent from your local council for building work that changes a property's size, appearance or use. Permitted development (PD) rights are a national grant of permission for common projects — many rear extensions, loft conversions and outbuildings — meaning you can build without a full application, provided the design stays inside strict limits on size, height and position.
When full permission is usually needed
- Flats and maisonettes — PD rights generally do not apply.
- Conservation areas, listed buildings and Areas of Outstanding Natural Beauty, where rights are reduced or removed.
- Properties where PD rights were removed by an "Article 4 direction" or by a condition on an earlier approval.
- Designs that exceed PD limits — for example wrap-around extensions, front extensions, or raised terraces.
- Changes of use, and most work that alters the front elevation facing the street.
Building regulations — a separate check
Building-regulations approval is separate from planning permission. Many extensions and alterations require approval, and some electrical, plumbing, heating, window and other works are covered by specific building-regulations routes. Some work is exempt or can be self-certified through a competent-person scheme. The correct route should be checked for the actual project rather than assumed from the planning position.
The Party Wall etc. Act 1996
The Party Wall etc. Act can apply where work is proposed on or at a shared boundary, to an existing party wall or party structure, or where excavation is planned close to and below neighbouring foundations. The notice requirements depend on the work and property relationship. It is separate from planning permission and building-regulations approval, so one approval does not replace the others.
Before you build a programme around an approval date
Decision targets and validation times vary by application type and authority, and an incomplete application can delay the clock before substantive review even begins. Check the current target published by the relevant council when you plan the project, and allow time for drawings, surveys, neighbour procedures and any requested amendments.
How Hamiltonn helps
We can identify the planning and building-control questions that need to be resolved before pricing or construction, and coordinate with architects, engineers, surveyors or building-control professionals where the project requires them. Formal planning and legal positions remain property-specific and should be confirmed through the appropriate authority or adviser.
Official sources for further checking
- GOV.UK: permitted development rights for householders
- GOV.UK: building regulations approval
- GOV.UK: party walls and building work
Published by Hamiltonn Home Improvement. Updated 9 August 2026 after review against the official sources above.
Planning rules change and every property is different — this guide is general information, not formal planning advice. We will confirm the position for your specific property before any work is priced.