Usually, and usually with a form. Two conservation areas cover this stretch of the valley. Getting on for two hundred listed buildings sit in the surrounding area. Plenty of people here are altering their homes right now, so this is not a village frozen in aspic. The real question is not whether you can extend, it is how many other parties get a vote before you start.
There are 181 listed buildings in the area, of which 173 are grade two and 8 are grade two star. Not one is grade one, which around here counts as a gap in the market. Listing is the strictest of the everyday constraints a homeowner meets. It applies to the whole building rather than the pretty bits, it covers the inside as well as the outside, and it reaches structures within the curtilage, so the garage and the garden wall can be caught by it too. Replacing windows, opening up a chimney breast, or putting rooflights on a rear slope all become applications for listed building consent rather than decisions you make with a builder over a cup of tea.
Two conservation areas cover the immediate ground, one at Batheaston and one at Bathford. Designation does not freeze a house, but it does change the rules around it: demolition needs consent, trees are protected, and permitted development rights can be trimmed back so that things you could do freely elsewhere need an application here. Materials and detailing get scrutinised in a way they are not on an unremarkable estate road, which is precisely what people are paying for when they buy in.
One scheduled monument sits within the area. That is the strictest protection tier in the country and it matters mainly for land next to it rather than for houses generally, but if a plot adjoins it, anything involving the ground brings a separate consent regime with it.
For evidence that all of this is navigable rather than fatal, the planning register for Bath and North East Somerset carries 3,302 applications between April 2024 and June 2026, with 1,417 of those in the most recent twelve months. That is an authority-wide figure covering the city as well as the villages, and it describes a planning system in constant use. People here extend, convert lofts, replace windows and build garden rooms. They just do it through the front door of the process.
Practically, the split is simple enough. If the house is unlisted and outside both conservation area boundaries, ordinary permitted development rights are likely to apply and a rear extension or loft conversion may not need a full application at all. If it is listed, assume consent for almost anything that touches fabric or appearance. If it is inside a conservation area, assume the permitted development rules are narrower than the national default and check which ones have been withdrawn before drawing anything. The order that saves money is boundary first, listing status second, architect third. Estate agents describe houses as being in a conservation area when it flatters the postcode and forget to mention it when it does not, so the council's own mapping is the version that counts.
Freedom to alter a house here is on the restricted side. Nothing is impossible, but the combination of two conservation areas and 181 listed buildings means the paperwork is part of the purchase rather than an afterthought, and the timetable belongs to the planning department rather than to you.