Yes, in most of Erith. The ground under the house will give you more trouble than the council will. There are only eleven listed buildings, none of them at the top grade. Six conservation areas cover parts of the town, and they are where most of the planning restrictions apply. Neighbours file hundreds of planning applications a year, and almost the whole area sits on clay that moves. In Erith, the structural engineer will have more to say about your extension than the conservation officer.
Historic England lists 11 buildings in and around Erith: none at Grade I, 2 at Grade II* and 9 at Grade II. Changing a listed building inside or out needs listed building consent on top of any planning permission. That includes small jobs such as replacing windows or knocking through an internal wall. Erith received a royal charter for a market in 1315, and yet it has left only eleven listed buildings, none of them at the top grade.
Bexley Council has designated 6 conservation areas here: Erith Riverside, Brook Street, Erith Road, Lesney Park Road, Oak Road and Woolwich Road. Inside them, anything visible from the street gets closer scrutiny, including side extensions, roof changes and new windows. Knocking a building down also needs consent. Ask Bexley Council whether a particular address is inside one of the six and whether any extra restrictions apply to it. Conservation area boundaries can run down the middle of a road, so the two sides may come under different rules.
The area has 1 scheduled monument, the strictest tier of protection in England. It only matters if your land is next to it.
Bexley Council received 555 planning applications from Erith between April 2024 and June 2026, 261 of them in the last twelve months. That shows plenty of owners here are changing their homes, mostly a loft or a back extension at a time.
The British Geological Survey's shrink-swell hazard reaches class 3 in Erith, and about 88% of the area's postcodes are at that class or above. Shrink-swell clay expands when wet and shrinks when dry, so it moves with the weather and with any nearby trees. For an extension, that usually means deeper foundations and a structural engineer's design from the start. Builders here should expect it as standard, and it doesn't mean the house is at risk. The clay was here long before any of Erith's listed buildings.
In practice, a house outside the six conservation areas can often take a modest rear extension or loft conversion under permitted development rights, with no full planning application. Inside a conservation area those rights are narrower. A listed building always needs consent. Flats make up about a third of Erith's homes, and they have no householder permitted development rights at all, so even small changes need permission.
Erith gives you a moderate amount of freedom to extend. Most streets are easy to work with, the six conservation areas need more care, and the clay sets limits everywhere.