South London is where the biggest extensions get built. Larger gardens, more semi-detached and detached stock and less blanket designation than the north mean permitted development still does real work here — but Wandsworth, Lambeth and Richmond each apply their own tests.
Twelve boroughs south of the river, from the dense Victorian terraces of inner Lambeth and Southwark to the interwar and post-war suburbs of Bromley, Bexley and Sutton.
The dominant brief south of the river is the ground-floor remodel: a side return infilled, a rear extension pushed back three or six metres, and the kitchen relocated across the full width. It is the single highest-value change available to a Victorian terrace, and it is why the larger home extension prior approval route matters more here than anywhere else in the capital.
That route allows a single-storey rear extension of 6 metres on a terraced or semi-detached house and 8 metres on a detached house, decided in six weeks at £249 after a 21-day neighbour consultation. It applies to houses only, never to flats, and it is withdrawn wherever an Article 4 direction operates — but across the outer South London boroughs it remains genuinely usable.
Three recur often enough to be worth checking before design starts.
| Package | Fixed fee | Turnaround |
|---|---|---|
| Essentials — measured survey, existing and proposed plans | 14–20 working days | |
| Loft conversion package — survey, plans, sections, elevations | 14–20 working days | |
| Mansard / roof rebuild package | 18–24 working days | |
| Complete — planning plus building regulations drawings | 20–28 working days |
We cover twelve: Lambeth, Southwark, Wandsworth, Lewisham, Croydon, Bromley, Merton, Sutton, Greenwich, Bexley, Kingston upon Thames and Richmond upon Thames. Each is a separate planning authority with its own Local Plan and validation list.
Often yes, through the larger home extension prior approval route: 6 metres on a terraced or semi-detached house, 8 on a detached house, decided in six weeks at £249 after a 21-day neighbour consultation. It is unavailable on flats and wherever an Article 4 direction applies.
Only if the property sits in Flood Zone 2 or 3, which affects parts of Richmond, Kingston, Wandsworth, Lewisham and Greenwich near the Thames and its tributaries. We check the zone at quotation stage, because it affects floor levels and rules out some basement schemes.
They can be, in two ways. A Tree Preservation Order or conservation-area tree within influencing distance requires an arboricultural report at £400 to £900. Separately, South London's shrinkable clay means foundations near mature trees are often taken to 2.5 metres or deeper.
Before you commit, it is worth understanding what it costs and seeing why homeowners choose us. You can search the site to find the right fit, or create a free account to track your project. When you are ready, get a quote in minutes — most homeowners have a fee in minutes — or contact us for a chat and a chartered technologist will be in touch.
