You can extend most houses in Dartford, but the old town and its conservation areas come with more paperwork than the rest. Close to a hundred buildings are listed. Five areas fall under conservation rules. Three ancient sites are protected outright. The neighbours still send in plans at a steady rate. Away from the historic core, the post-war semi is mostly yours to change.
Dartford has 92 listed buildings. Two are Grade I, five are Grade II* and the other 85 are Grade II. Listing covers the whole building, inside and out, so changing a listed home needs listed building consent on top of any planning permission, and that applies even to internal walls, windows and fireplaces. Grade I and II* are the most tightly controlled, though Grade II is still a real constraint. Most of the town's homes are not listed. The ones that are tend to belong to owners who end up on first-name terms with the council's conservation officer.
The area has five conservation areas: Dartford Town Centre, Star Hill, Oak Road, Iron Mill Lane and Church Hill in Wilmington. Inside them, the council looks harder at anything that changes how a street looks, and work that would go ahead freely elsewhere can need permission, especially at the front of a house. Dartford Borough Council publishes the boundaries. Check the exact address against that map, and ask for the property's planning history while you are at it, because boundaries do not always follow the line a buyer assumes.
There are 3 scheduled monuments in and around the area, the strictest protection there is. They only matter for land on or next to one, which few house buyers will ever need to worry about.
Dartford Borough Council received 3,129 planning applications between April 2024 and June 2026, including 1,318 in the last twelve months. People here clearly do change their homes, and they file the paperwork to do it. The bigger schemes are the ones that struggle. The plan for a Tesco superstore on Lowfield Street ran into planning problems and the recession and was dropped in 2015, while the loft conversions kept going.
For an unlisted house outside the five conservation areas, many rear extensions and loft conversions can go ahead under permitted development without a full application, within national limits on size and position. Inside a conservation area, more of that work needs a formal application. For a listed building, assume almost everything does. Henry VIII pulled down the priory in 1538 and built a manor house on the site, and he is about the last person in Dartford known to have rebuilt something without asking first.
Dartford gives you less freedom to alter a home than you might expect from a commuter town. Outside the historic pockets most projects stay simple, but on the protected streets the council has a real say in your plans.