Yes, for most homes, but Dover has more history per street than most towns its size. Close to two hundred buildings are listed. A handful carry the top grade. Ancient monuments sit on the hills above town. The neighbours keep applying for extensions anyway. For an ordinary house, an extension is paperwork. For the wrong house, it's a negotiation with several centuries.
Historic England lists 178 buildings in the area: 4 at Grade I, 15 at Grade II* and 159 at Grade II. Listing covers the whole building, inside and out, so replacing windows, removing a wall or adding a rear extension usually needs listed building consent on top of any planning permission. Grade II is where most people end up. Grade I and II* are the tiers where the conservation officer holds opinions about your guttering. If the house you're viewing is on the list, the estate agent will call it "full of character". Your builder will call it something else when the quote arrives.
There are also 14 scheduled monuments, the strictest tier of protection. They matter mainly if your land borders one or sits on top of something old, which in a town that has been defended since before the Normans is less unlikely than it sounds.
People do extend here, and often. Between April 2024 and June 2026 the area logged 1,245 planning applications, 522 of them in the twelve months to June 2026. That's steady evidence that loft conversions, rear extensions and new windows are routine business in Dover, not a fight with the council every time.
In practice, most unlisted houses can use permitted development rights for many smaller changes, such as modest rear extensions and some loft work, without a full planning application, within national size limits. A listed building doesn't get that shortcut, and neither does work that affects a protected monument's setting. The honest first step before buying is to check whether the house is listed and whether it sits near anything scheduled, then ask Dover District Council before assuming anything. It's a lot cheaper to ask than to reverse a kitchen you built without asking.
Most Dover homes can be extended with ordinary planning effort. The town's heritage still gets more say than it would in most places, so freedom to alter a home here is below average, and buyers of anything old should budget for the conversation.