Planning permission and approvals in London

Often not. Under permitted development, a single-storey rear extension on a house can project 3 metres from the original rear wall (terraced and semi-detached) or 4 metres (detached), be no more than 4 metres high, and must use materials similar in appearance to the existing house. The larger home extension scheme allows 6 metres or 8 metres respectively, subject to a prior approval application in which neighbours are consulted.

Permitted development does not apply to flats or maisonettes, to listed buildings, or where the council has removed the rights with an Article 4 direction, which is common in London conservation areas. Anything outside those limits needs a householder planning application, normally decided within eight weeks. We check which route applies at the site visit.

A lawful development certificate is the council's formal confirmation that a proposal is permitted development and does not need planning permission. It is optional, but we recommend it for extensions and lofts because solicitors ask for it when you sell, and it protects you if a neighbour later disputes the work. It follows the same eight-week process as a planning application but is judged on facts, not opinion.

Building regulations cover the safety and performance of the work: structure, fire safety and escape, insulation and energy, ventilation, drainage, electrics and glazing. They apply whether or not planning permission is needed. Either the council's building control team or an approved private inspector checks the drawings and inspects the work at set stages, from foundations to completion.

At the end you receive a completion certificate. Without it, you will have difficulty selling or remortgaging, so we build the inspections into the programme and obtain the certificate before handover.

The Party Wall etc. Act 1996 applies when you build on or up to the boundary, cut into a shared wall (for example to insert a steel beam), or excavate within 3 metres of a neighbour's structure and below their foundations, which covers most London extensions and basements. Notice must be served one or two months before work starts, depending on the type of work.

If your neighbour consents in writing, no further action is needed. If they dissent or do not reply, each side appoints a surveyor (or shares one) to produce a party wall award. We prepare and serve the notices and coordinate with the surveyors so the programme is not held up.