Yes, for most houses. Very few buildings here are listed. There is one conservation area, around the old town. The ground is the bigger constraint, and it matters below ground level rather than on the planning form. Outside the old town, the extension is usually straightforward to get permission for and more work to lay foundations for.
Historic England lists 23 buildings in the area. None is Grade I, one is Grade II*, and 22 are Grade II. Listing covers the inside as well as the outside, so almost any change to a listed building needs listed building consent on top of any planning permission. That includes things as small as windows, doors and internal walls. That is 23 houses out of a town full of post-war semis and terraces. For most buyers, listing will never come up, and the ones it affects will be told at the viewing.
There is one conservation area, the Queenborough conservation area, which covers the old heart of the town. Inside it, the council takes a closer interest in anything that changes the look of a street, such as frontages, roofs, windows and demolition. Some work that would be automatic elsewhere needs an application. Outside the boundary, those extra rules don't apply.
There is one scheduled monument, the site of Queenborough Castle. Scheduling is the strictest protection there is, and any work on or next to a monument needs separate consent. It only matters to a handful of plots near the site. Nobody's rear extension ends up needing it.
Swale's planning records show 30 applications in the area between April 2024 and June 2026, and 9 in the last twelve months. That is proof that people do alter homes here, in modest numbers. It says nothing about how many were approved, so treat it as evidence of activity, not of the council's mood.
The ground is where the real conditions are. The British Geological Survey puts the whole area in class 3 for shrink-swell clay, and every postcode reaches that class. Clay at that level swells when wet and shrinks when dry, and it moves most near trees and in long dry summers. The same survey also puts the whole area in class 3 for compressible ground. For an extension, that means deeper foundations than on firm ground and a structural engineer's report before the builder's quote. Neither is a reason to panic, but both cost money, and the builder's first price is unlikely to include them.
In practice, many single-storey rear extensions on an ordinary house outside the conservation area can go ahead under permitted development, the national rules that allow some building work without a planning application. A listed building or a house inside the conservation area should assume an application is needed. Anyone unsure should ask the council for a lawful development certificate before the builder starts. Building control applies everywhere, and here it will care about the foundations.
Queenborough is middling for extending. Most homes are free of heritage restrictions, and the difficulty is in the ground rather than the paperwork. The protected old town is the exception.