Yes, and you will be asking permission a great deal more often than you would in a town built after the invention of the photocopier. Two hundred and fifty listed buildings sit in and around the place. Three conservation areas cover the historic cores. Twenty-two scheduled monuments are dotted through the surrounding fields. People do extend here, routinely, but they do it with an application and an agent rather than a skip and a free weekend.
The listing register is the first constraint and the heaviest. Of those 250 listed buildings, 12 are Grade I, 16 are Grade II star and 222 are Grade II. Listing is not a rule about the front elevation. It covers the whole building, inside and out, and it catches the things people assume are their own business: internal walls, staircases, original windows, roof coverings, and anything bolted to the outside. Listed building consent runs alongside planning permission rather than instead of it, and doing the work first and asking afterwards is an offence rather than a negotiating position.
Three conservation areas add a second layer, covering Lostwithiel itself along with Lerryn and Tywardreath. Designation brings extra control over work that would be unremarkable elsewhere, and the precise scope varies between areas, so the designation's own documentation held by Cornwall Council is the thing to read before an architect draws anything.
Then there are the 22 scheduled monuments. That is the strictest protection tier in the system, and for most buyers it is irrelevant right up until it is decisive, which is when the land in question sits near one.
None of that means the town is frozen. Cornwall Council's planning register logged 157 applications across the area between April 2024 and June 2026, including 79 in the twelve months to June 2026. Householders here clearly do apply to change their homes, and in volume. What the register will not tell you is how any of them fared, so treat the activity as evidence that the process is navigable, not as a probability that yours succeeds.
Below ground there is a second, quieter set of paperwork. Half the postcodes in the area have a recorded mine working within 500 metres, and 14 sit directly over one. This is not coalfield territory and none of it implies a property is unsound. What it means practically is a mining search, possibly a specialist report on top of it, and the real possibility that a lender or an insurer asks a question your conveyancer needs an answer to. Budget the time rather than the anxiety.
One listed building in the area sits on Historic England's Heritage at Risk register. That is a building in poor condition, which can attract grant support and will attract attention, and it is a fact about that building rather than a warning to anyone buying an ordinary house down the road.
The practical division is straightforward. Off the list and outside the designated areas, the usual permitted development rights apply and a modest rear extension is a normal project. On the list or inside a conservation area, assume nothing is permitted until somebody in the planning department confirms it, and get that confirmation before exchange rather than after the builder has quoted.
Freedom to alter a home is one of the weaker parts of the offer here. The town is old, protected, and unapologetic about both, and the buyers who enjoy living in it are the ones who wanted the seventeenth century and understood that it came with a filing cabinet.