Yes, in most of Arborfield Garrison you can extend, because most of it is too young for anyone to want to protect. There are no conservation areas. Listed buildings are few for the size of the area. The neighbours are filing plans all the time. The heritage register is rarely what stands between you and a kitchen extension.
The surrounding area holds 95 listed buildings: two at grade I, four at grade II* and 89 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 ordinary planning permission, with the council expecting like-for-like materials and a good reason. If the house you are buying is one of the 95, the extension becomes a negotiation with history. If it is one of the thousands of homes built around them, the list is someone else's problem.
There are seven scheduled monuments in the area, the strictest tier of protection going. They matter mainly if your land sits next to one, where digging and building nearby can need separate consent. For a semi on a new estate, they are something to walk the dog past.
The planning records show how keen people are to change what they bought. Across the records covering the area from February 2024 to June 2026 there were 5,851 applications, 2,556 of them in the last twelve months. That is not a sign of what gets approved, and none of it predicts your own application. It does show that altering a home here is ordinary behaviour, not an act of rebellion. Nobody buys a four-bedroom new-build and stops at four bedrooms.
The ground deserves a look before the architect does. The British Geological Survey rates shrink-swell clay here at a maximum of class 3 on its published hazard scale, and about 2% of the area reaches that level. Clay that swells when wet and shrinks when dry can move shallow foundations, so an extension on the affected pockets may need deeper footings and a structural engineer's view. That is a cost line in the budget, not a reason to panic, and for most of the area it will not apply.
In practice, the lack of a conservation area means the usual national permitted development rules apply to most houses here, so a modest rear extension or loft conversion may not need a full application. The exception to check is the estate itself: the original planning permission for a newer development can restrict what owners may do without applying, and the only way to know is to read it or ask the council before drawing anything. Listed buildings sit outside permitted development entirely.
Freedom to extend here is middling: no conservation areas and a young housing stock make most projects straightforward, while the listed buildings, the scheduled monuments and a few clay pockets are the checks worth doing first. The biggest constraint on most extensions will be the size of the garden, not the heritage register.