Yes for most houses here, and firmly no for a specific few. Most of the town is twentieth-century stock carrying the usual permitted development rights. The old core is a different proposition entirely. Plenty of households are altering their homes right now. The question is never whether Cullompton allows it, only which side of the listing line your particular house sits on.
There are 56 listed buildings inside the area: two at Grade I, two at Grade II*, and 52 at Grade II. Listing covers the whole building, inside and out, along with anything attached to it. Replacement windows, a new front door, taking out an internal wall, render, rooflights: each of those stops being a weekend job and becomes an application. Grade II is the common tier and the least restrictive of the three, which is a comparison rather than a comfort.
One scheduled monument sits within the area, the Roman forts and camps on the hill to the north-west of the centre. Scheduled monument consent is the strictest tier in the whole system, and it governs the ground rather than any building on it, so it only enters the conversation if your plans involve a digger near the earthworks.
For live evidence of what actually happens, the planning record carries 575 applications across the area between April 2024 and June 2026, 272 of them in the final twelve months of that window. That is not the profile of a place where households have given up on the idea of applying.
One listed building in the area appears on Historic England's Heritage at Risk register. That designation describes a building in poor condition whose repair may attract grant support and will certainly attract attention, rather than anything that touches the ordinary houses around it. It is a useful reminder of what deferred maintenance costs on a structure nobody is permitted to simply modernise.
In practice, around 19% of dwellings here were built before 1930, so most buyers are working with standard permitted development rights rather than consent applications: rear extensions, loft conversions and outbuildings inside the usual limits. The town centre has held conservation area protection since 1977, and inside a conservation area those rights are trimmed rather than cancelled. The move for anyone buying in the old part of town is to establish what is listed and what is merely old before paying anybody to draw plans, because those two words behave very differently once a form is involved.
Freedom to alter a home here sits somewhere in the middle: routine across most of the town, seriously constrained on the handful of frontages carrying the heritage. Find out which one you are buying before you fall for the beams.