Yes, you can extend most houses in Belvedere, but more of the town is protected than you'd guess from the station platform. There are dozens of listed buildings in and around it. Eleven conservation areas cover parts of the town and its edges. There's shrinkable clay under almost every postcode. The neighbours are applying for planning permission at a steady rate, so it can clearly be done.
Historic England lists 62 buildings in and around Belvedere: four at Grade I, three at Grade II* and 55 at Grade II. Listing protects the whole building, inside as well as out, and almost any change to its character needs listed building consent on top of planning permission. With most of those at Grade II, a buyer is more likely to end up living next to one than in one.
There are 11 conservation areas within the boundary drawn around the town, some of them reaching into Erith next door. Woolwich Road is the one in Belvedere itself, designated by Bexley Council in 1992 to protect the Victorian villas and semis along Woolwich Road and Gloucester Road. Inside a conservation area the council looks harder at anything visible from the street, and demolition, front extensions and changes to the roofline can need consent that wouldn't be needed two roads away. Check the council's conservation area map for the exact house, because the boundaries are drawn street by street.
There are also three scheduled monuments within that boundary. That's the strictest level of protection, and it matters mostly for land right beside one.
Bexley Council's planning register shows 349 applications in Belvedere between April 2024 and June 2026, including 139 in the last twelve months. Those are neighbours putting in loft conversions, back extensions and new windows. Sir Culling Eardley built Belvedere and then sold it off a plot at a time, and the town is still changing in small pieces like that.
The ground needs as much thought as the paperwork. The British Geological Survey puts the area's highest shrink-swell class at 3, and about 98% of postcodes reach that class. Clay that shrinks in dry summers and swells in wet winters can move shallow foundations, so any extension here needs a structural engineer to set the foundation depth, especially near big trees. It adds cost and a bit of time.
One listed building in the area is on Historic England's Heritage at Risk register. That's a building in poor repair, which may get grant money and will certainly get scrutiny if anyone works on it. It has no bearing on an ordinary semi down the road.
In practice, most houses outside the conservation areas and the listed buildings can be extended to a modest size under permitted development rights, without a full planning application. Once a house is listed, inside a conservation area or being extended beyond those limits, ask Bexley Council early and design with its view in mind.
Freedom to extend is one of Belvedere's weaker points. The rules are tighter than the town's size suggests, and the clay adds a cost even where the planners don't object.