Usually yes, but check the map before you call the architect. Nearly a hundred buildings are listed. Four conservation areas cover parts of the town. The neighbours send in hundreds of planning applications a year. Extending here is routine, as long as the house you've bought isn't one of the exceptions.
Oxted has 91 listed buildings. Three are Grade I, 9 are Grade II* and 79 are Grade II. Listing protects the whole building, inside and out, so works that change its character need listed building consent as well as any planning permission. That covers the extension, the replacement windows and, in some cases, the kitchen someone put in during the 1970s. Grade II is by far the most common tier here. Grade II can still say no, so the difference from Grade I is how much room there is for argument, not whether the rules apply.
There are 4 conservation areas: Oxted, Station Road West, Broadham Green and Spring Lane, and Limpsfield. Inside one, the rules tighten. Some of the extension and alteration rights that apply automatically elsewhere shrink or disappear, and the council starts caring about materials, roof lines and what the house looks like from the street. Whether any of these areas carries extra restrictions on top is a question for Tandridge's planning team, not an assumption to make at the viewing.
There is 1 scheduled monument in the area, the strictest protection tier of all. It matters mainly if your land is next to it. Anyone buying a house with a medieval earthwork at the end of the garden should expect the earthwork to win.
The neighbours aren't put off. Between April 2024 and June 2026, 647 planning applications were submitted here, 308 of them in the last twelve months. That's a town permanently adding a room, a porch or a loft somewhere, and the sound of scaffolding is part of the local soundtrack. It doesn't tell you how many were approved. It does tell you nobody in Oxted regards their house as finished.
In practice, most houses outside the conservation areas and off the listed register can use permitted development rights for modest extensions and loft work without full planning permission. Some still need prior approval or a lawful development certificate to prove it. Inside a conservation area, or at a listed address, assume you need consent until the council tells you otherwise. Check which category the house falls into before you make an offer. Your solicitor's searches will tell you eventually, and eventually is expensive.
Freedom to extend in Oxted is middling. It's generous on ordinary post-war streets and tight in the historic pockets, so which house you buy matters more than which town it's in.