Permitted Development vs Planning Permission
Permitted development allows some home improvements to be carried out without a full planning application, provided the work stays within strict national rules. Planning permission is needed when the proposal falls outside those rules or when local constraints require the council to assess the design.
The main difference is certainty. Permitted development can be quicker, but it is only suitable when the proposal clearly fits the rules. Planning permission takes longer, but it allows the council to assess a wider design and can be the better route when the home sits in a sensitive location.
In practice, many clients still apply for a lawful development certificate when using permitted development. This gives written confirmation that the work was lawful at the time of construction, which can be helpful when selling or remortgaging the property.
Flats, maisonettes, listed buildings and some conservation area properties have fewer permitted development rights. Previous alterations can also affect what is still available, so it is important to check the planning history before assuming the route is simple.
Practical checklist
✅ Use permitted development only when the design clearly fits the rules.
✅ Use planning permission where the proposal needs council assessment.
✅ Apply for a lawful development certificate if you want formal confirmation.
✅ Do not assume permitted development applies to flats, maisonettes or listed buildings.
✅ Check conservation areas, Article 4 directions and previous extensions.
✅ Keep drawings accurate, measured and clear whichever route you choose
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Areas we work across in South London
Barnes Design is based in South West London and works with homeowners, developers and business owners across nearby South London areas. For permitted development advice, planning applications and lawful development certificates, we regularly support clients in and around Wandsworth, Balham, Clapham, Tooting, Wimbledon, Battersea, Streatham, Putney, Fulham, Kingston upon Thames and the surrounding boroughs.
Local planning context matters. Streets of Victorian and Edwardian terraces, conservation areas, maisonettes, mansion blocks, period family homes and small development sites can all need a slightly different design and planning approach.
