You can extend a house in Woodstock, but in the old town expect to ask permission for a great deal of it. The town is full of listed buildings. Its historic core is a conservation area. The neighbours apply for planning permission constantly, so the process plainly works. It also takes longer than the builder's quote assumes.
Historic England lists 192 buildings in Woodstock. Five are Grade I, ten are Grade II* and 177 are Grade II. Listing covers the whole building, inside and out, so changes that affect its character need listed building consent from the council on top of any planning permission, and that can include replacing windows, moving internal walls or changing a roof covering. Grade II is the commonest grade and still a legal protection, and doing the work first and asking afterwards is a criminal offence. The town spent the 16th century making gloves, and the consent process expects about the same delicacy.
The town has one conservation area, and it carries Woodstock's name. Inside it, the council looks hard at anything visible from the street, including extensions, roof alterations and demolition, and the rules for work without an application are narrower than on an ordinary estate. A house can be unlisted and still be inside the conservation area, so the age of the brick does not tell you which rules apply. Ask West Oxfordshire District Council to confirm in writing whether the house is listed, inside the conservation area or both, because the rest of the plan depends on that answer.
One scheduled monument falls within the area, the strictest protection there is, and it matters mainly to anyone whose land touches it. The last big building project in Woodstock cleared what was left of a royal palace to make room for a bigger one. The protection rules exist to make sure nothing like it happens again.
Residents are not deterred. West Oxfordshire's planning register logged 320 applications in Woodstock between April 2024 and June 2026, 149 of them in the most recent twelve months. People here extend, alter and rebuild all the time, and they fill in forms first.
Underfoot, the British Geological Survey rates shrink-swell clay at class 3 at its highest across the area, reaching that class across about 34% of it. Clay at that level swells when wet and shrinks when dry, which matters for new foundations, especially near trees. In practice it means a structural engineer's view on foundation depth before the extension is drawn, and building control will usually ask the same question. It is a routine design issue, and the house will not be falling into a hole.
Away from the listed streets and the conservation area, the post-war parts of Woodstock behave like most English housing, and a modest rear extension may fall within permitted development. In the historic core, assume everything needs an application until the council says otherwise, and budget time for the conversation.
Freedom to extend in Woodstock is middling. The newer streets let you get on with it, and in the old town the paperwork wins every time.