Extending in Northampton depends on whether your plot was ever a working one, and in the older parts of town a surprising number were.
In the Boot and Shoe Quarter the rear yard behind a terrace was not a garden. It was working space, and it often had a small workshop or outbuilding at the end of it. Those buildings frequently survive, converted into sheds, garages or earlier extensions, and they matter to an extension project in two ways. They may occupy exactly the footprint you want, and they may be considered part of the industrial fabric the conservation area exists to protect, which makes demolishing them a different conversation from clearing a garden shed.
The upside is that these plots frequently have rear access, because the yards needed servicing. A back entry transforms the practicality and the cost of an extension compared with a terrace that has none, and it is one of the first things we look for.
Out on the interwar, post-war and modern housing the picture is ordinary. A single storey rear extension of up to four metres on a detached house or three on a semi can fall within permitted development, with side access and a drive for the skip. Inside any of the town’s twenty conservation areas those limits reduce and a side extension loses its permitted development rights.
There is also the larger home extension route on unlisted property: up to eight metres on a detached house or six on any other, by prior approval rather than full permission, with neighbours notified and an answer in about six weeks.
Our extensions work is described in more detail there, including how the inspections fit around the build.