Yes, in most of Rush Green you can extend, with the usual paperwork and a closer look at what's under the floor. Listed buildings are few and scattered. Conservation areas only reach the edges. The neighbours put in planning applications at a steady rate. The ground is the bigger obstacle, more than the planners.
Rush Green has 29 listed buildings: none at Grade I, two at Grade II* and 27 at Grade II. Listing covers the whole building, inside and out, and any change that affects its character needs listed building consent on top of planning permission. For the owner of an ordinary interwar semi none of that applies. With no Grade I building on the list, the strictest rules here apply to a small number of buildings that most buyers will never own.
Two conservation areas reach onto Rush Green's map: Romford, and the Chadwell Heath Anti-aircraft Gun Site. Inside a conservation area the council can ask for consent on changes that would elsewhere go ahead without it, such as some alterations to frontages, roofs and boundary walls, and demolition. The council's conservation area map is the first check for any house near either boundary, since one side of a road can face rules the other side never sees.
The neighbours are not waiting for permission to dream. The council's planning records show 698 applications across Rush Green from April 2024 to June 2026, 297 of them in the most recent twelve months. Extending a house here is a normal thing to do, and the scaffolding to prove it is easy to spot.
The ground is where the care goes. The British Geological Survey puts the whole of Rush Green in class 3 for shrink-swell, its hazard rating for clay that swells when wet and shrinks when dry. For an extension that means foundations dug deeper than a builder might quote by default, extra caution near large trees, and a structural engineer's opinion before the foundations go in. The clay ignores whatever the planning permission says.
Outside the two conservation areas and away from the listed buildings, most single-storey rear extensions and many loft conversions on a semi or terrace can go ahead under permitted development, the national rights that let homeowners make set changes without a full application, as long as the house stays within their size limits. Anything bigger, anything on the front, and anything on a flat goes to the council as a full application. Flats make up a large share of Rush Green's homes, and their owners mostly have to ask first.
Rush Green gives a homeowner a middling amount of freedom. The heritage rules are light, but the clay underfoot and the planning rules for flats mean most projects still need some careful work first.