You can extend a house in Totnes, and you should assume that anything visible from the street begins with a form. There are 324 listed buildings in the area. Five scheduled monuments as well. Hundreds of applications still go in every year. The answer is not no. The answer is yes, slowly, in writing, with drawings.
Historic England's register carries those 324 listings as six at Grade I, 28 at Grade II star and 290 at Grade II. Listing is not a rule about the front elevation. It covers the whole building, inside and out, so replacing a staircase, opening up a blocked fireplace or swapping draughty windows for something that holds heat all become applications for listed building consent rather than decisions you make on a Saturday. Grade II is the workhorse tier and the one most buyers here actually land in, which is worth knowing before falling in love with a room on the strength of its original panelling.
Five scheduled monuments sit inside the area too. That is the strictest tier in the whole system, and it matters chiefly if a boundary happens to touch one, at which point works to the ground can require their own consent quite separately from anything standing on it.
None of which stops people building. The planning record carries 944 applications across the area between April 2024 and June 2026, 388 of them in the most recent twelve months. Whatever the constraints look like on paper, this is plainly not a town where nobody bothers applying.
Two of the listed buildings here appear on Historic England's Heritage at Risk register. That is a statement about the condition of a specific building rather than about the street it stands on. Repair work of that kind can attract grant support, and it will attract scrutiny, so a building in that category is a project with an audience rather than a quiet private renovation.
For an ordinary unlisted house away from the protected stock, permitted development rights apply here as they do anywhere, and a modest rear extension or a loft conversion may need no more than a lawful development certificate and a builder who returns calls. Once a property is listed, or physically attached to one that is, those rights narrow sharply, and the sensible order is to ask the council's conservation officers what they will accept before paying an architect to draw what they will not. Check the listing entry for the exact address rather than assuming the rest of the terrace speaks for your half of it.
Freedom to alter a home is the tightest thing about owning one in Totnes, and it is the bargain the town struck with itself, because the streets look the way they do precisely because somebody says no with some regularity. Buy the unlisted post-war semi if you want a wall gone by Christmas, and buy the listed one only if the correspondence is part of what you came for.