You can extend a house in Tooting, but on a lot of streets the council has a say in what it looks like. There are a dozen conservation areas in and around it. Dozens of buildings are listed. All of it is on clay that shrinks and swells. The neighbours keep applying anyway.
Tooting has 65 listed buildings: one at Grade I, none at Grade II*, and 64 at Grade II. Listing covers the whole building, inside and out, so any change that affects its character needs listed building consent on top of any planning permission. Almost all of Tooting's listed buildings are Grade II, the everyday grade, and that's still enough to make a new kitchen extension a formal application.
There are 12 conservation areas in and around Tooting, including the Heaver Estate, Nightingale Lane, Magdalen Park, Culverden Road and Dinsmore Road. Inside them, the council looks harder at anything that changes how a street looks, from roofs and front elevations to demolition and trees. A loft dormer that's routine outside a boundary can turn into a long conversation about roof slates inside one.
The council recorded 1,922 planning applications in Tooting between March 2024 and June 2026, 865 of them in the last twelve months. Whatever you have in mind for the back of an Edwardian terrace, someone a couple of streets away has probably already applied for the same thing.
The ground needs attention too. The British Geological Survey puts Tooting at class 3 on its shrink-swell scale, and that class covers the whole area. Clay like this swells when wet and shrinks when dry, so extensions here often need deeper foundations and a structural engineer's view, especially near large trees. It's a common, manageable condition, but your builder needs to plan for it.
Two of Tooting's listed buildings are on Historic England's Heritage at Risk register, which means they're in poor condition. Repairs to them may get grant support and will get close scrutiny. That's a matter for whoever owns those two buildings, not the owner of an ordinary house nearby.
In practice, a house outside a conservation area can often add a modest rear extension or loft conversion under permitted development rights without a full planning application. Inside a conservation area those rights are narrower, and for a listed building almost everything needs consent. Most homes in Tooting are flats, and flats don't get the householder permitted development rights that houses do. If you think a project needs no permission, apply to the council for a lawful development certificate first. It's the cheapest way to settle the question in writing before work starts.
You can extend in Tooting, but freedom to alter a home is limited, and on the conservation streets the council has most of the say.