Yes, for most houses in Dagenham, though the ground has more say than the heritage rules. Listed buildings are few. Two conservation areas cover the older corners. Neighbours put in planning applications all the time. The clay under the whole town is the part that gets expensive.
Dagenham has 10 listed buildings, none at Grade I, 2 at Grade II* and 8 at Grade II. Listing protects the whole building, inside and out, so any change that affects its character needs listed building consent from the council on top of any planning permission. With ten of them across an area of several thousand homes, the odds that the house you're viewing is one of them are slim, and the conveyancing searches will tell you if it is.
The area has 2 conservation areas, Dagenham Village and Mayfield. Inside a conservation area, the council takes a closer interest in anything visible from the street, including front extensions, roof alterations, cladding and demolition, and some changes that would otherwise go ahead without an application need one. Find out whether the house falls inside either boundary from Barking and Dagenham council's conservation area maps, early on, because the answer decides which set of rules the drawings have to meet.
The neighbours are busy. Between March 2024 and June 2026, 833 planning applications were lodged in Dagenham, 361 of them in the last twelve months. On an estate where the houses were built to a few repeated designs, everyone can see how far the extension next door sticks out, and that is usually the first thing the next application gets measured against.
The ground matters more. The British Geological Survey puts Dagenham's shrink-swell hazard at class 3, and 100% of the area reaches that class. Shrink-swell means clay that expands when wet and shrinks when dry, and over time that movement can crack foundations that aren't deep enough. For an extension, it usually means deeper foundations than a builder might quote off the cuff, and a structural engineer's view before the price is agreed. Large trees near the footings make the problem worse, and on the planning drawings they look like a nice feature in the garden.
Historic England has one listed building in the area on its Heritage at Risk register. That means a building in poor condition, whose repair may qualify for grant support and will be watched closely while it happens. For the owner of an ordinary terrace a few streets away, it changes nothing.
In practice, a house outside both conservation areas and off the listed register can often take a modest rear extension or loft conversion under permitted development, the national rights that let some work go ahead without a full planning application. Anything larger, anything on a listed building, or anything visible inside Dagenham Village or Mayfield goes through the council in the ordinary way. A lawful development certificate from the council confirms in writing that a project doesn't need permission, and it is far cheaper than finding out afterwards that it did.
Freedom to extend in Dagenham is middling. The heritage rules are light across most of the town, the clay is a cost on every project, and the two conservation areas are where most of the paperwork piles up.