Yes, you can extend most homes in Poyle, because very little of it is old enough for anyone to want to protect. There is no grade I building in the area. There is one conservation area, and it is Colnbrook's. The neighbours apply for planning permission all the time. Most of the history is next door, and so is most of the paperwork.
Historic England lists 24 buildings across the wider area around Poyle. None is grade I, two are grade II* and 22 are grade II. Listing covers the inside of a building as well as the outside, so changing a listed home needs listed building consent on top of any planning permission, and that covers windows, doors and internal walls as much as extensions. Only about 9% of the village's homes were built before 1930, so the chance of buying one of those 24 by accident is low. The protected buildings are mostly the old churches and big houses of the villages around Poyle.
There is one conservation area in the wider area, Colnbrook. Inside it, the council looks harder at anything that changes how a building looks from the street, including demolition, extensions, dormers and some tree work, and the design has to suit the old village around it. Inside that boundary, a buyer is negotiating with several centuries of coaching-road frontage. Outside it, which covers most of Poyle, the post-war estates carry none of that.
Neighbours are not shy about applying. Between April 2024 and June 2026 there were 1,420 planning applications in the area, 649 of them in the last 12 months. Altering a building here is routine, and the council's planning register is busy enough that any nearby application will turn up on it.
For most houses in Poyle, smaller rear extensions, loft conversions and outbuildings can often go ahead under national permitted development rules without a full planning application. The exceptions are listed buildings, homes in the conservation area and any estate where the council has removed those rights. Flats make up about 38% of Poyle's homes, and they generally need consent for changes a house could make without asking. Ask Slough Borough Council whether permitted development rights still apply to the house you are buying, and get the answer in writing. A semi built after the war can usually be extended. A flat above a shop is a longer conversation.
Poyle's freedom to extend is middling. Heritage rules rarely get in the way outside Colnbrook's conservation area, but flats and the occasional listed building still mean asking first.