You can extend in Gillingham, but the town's history gets a say first. Hundreds of listed buildings sit in and around it. There are 14 conservation areas. There are 50 scheduled monuments. The neighbours put in planning applications anyway, constantly. Before you sketch the loft conversion, find out whether your house sits in the protected part of town.
The surrounding area holds 213 listed buildings: 16 at Grade I, 44 at Grade II* and 153 at Grade II. Listing covers the whole building, inside and out, so changes to a listed home need listed building consent on top of any planning permission. Grade I and Grade II* are the top tiers, and 60 of them in one patch is a heavy load, much of it tied to the old dockyard and its defences. If the house you're buying is listed, the kitchen you're picturing will come with a conversation about sash windows.
There are 14 conservation areas in and around the town, including Gillingham Green, Gillingham Park, Lower Rainham, Lower Twydall and Brompton Lines. Being in one tends to mean tighter control over what the outside of a house can become, and more changes need consent that would go through without it elsewhere. Estate agents call it "character". The planning department calls it paperwork.
The area also contains 50 scheduled monuments, the strictest tier of protection. They matter mainly if your land sits next to one, and Gillingham's are largely forts, lines and dockyard structures. The town spent the 18th century building defences against invasion, and its planning system has kept the habit.
People extend here all the time. Between April 2024 and June 2026, 3,862 planning applications were logged across the area, and 1,637 of them came in the last 12 months. That doesn't tell you how many were approved. It does tell you that the side return and the rear dormer are a normal ambition in Gillingham, not a reckless one.
One listed building in the area is on Historic England's Heritage at Risk register. That means a building in poor condition whose repair may attract grant support and will certainly attract scrutiny. It isn't a hazard to anyone buying an ordinary house down the road.
In practice, for a house that isn't listed and sits outside the conservation areas, many modest extensions can go ahead under permitted development without a full planning application. A listed building, or a house inside a conservation area, loses some of that freedom and will need consent for work that would be routine elsewhere. Check the listing and the conservation-area boundary for the exact address before an offer, not after the builder has quoted.
Freedom to alter a home is Gillingham's weak spot. So much of the surrounding area is protected that any buyer with big plans should assume the answer starts with "apply first".