Yes, in most cases. The village has only a handful of listed buildings. It has no conservation area. Most of the homes are ordinary post-war houses with nothing protected about them. The main thing to check is the ground under the extension, because the rules above it are fairly light.
Historic England lists 10 buildings in White Waltham. None is Grade I, 2 are Grade II* and 8 are Grade II. Owning one of those ten means listed building consent for almost any change, inside or out, and the council's conservation officers will take an interest in matters as small as the window catches. Anyone buying one of the other houses doesn't face any of that. Roman coins and tiles have been dug up in the parish, and the church dates back to the Normans, yet the old place has left very little paperwork for the people building on it now.
The planning records behind this page log 3,607 applications between April 2024 and June 2026, and 1,638 in the last twelve months. Those records cover the wider surrounding area, so the figure goes beyond the village itself, but it is plain evidence that people around here are extending, converting and rebuilding all the time. A buyer who wants another bedroom will have plenty of company.
The ground needs more thought. The British Geological Survey rates the area at class 3 for shrink-swell clay, and 100% of the area's postcodes reach that class. Clay that shrinks in dry summers and swells in wet winters moves foundations about, so an extension here may need deeper foundations than a builder from sandier country would quote. Big trees close to the new footings make it worse. None of this stops anyone extending. It means paying for a structural engineer's view before agreeing a price with the builder, not after the cracks appear.
In practice, most homes in White Waltham keep the normal permitted development rights. That covers many single-storey rear extensions, loft conversions and outbuildings without a full planning application, provided they stay within the national size limits. Anything bigger, or anything touching one of the ten listed buildings, goes to the Royal Borough of Windsor and Maidenhead for consent. Before buying, ask the council whether the specific property has had its permitted development rights removed by an earlier planning condition. Particulars that promise "scope to extend" rarely check.
White Waltham is one of the easier places in the borough to extend. Heritage rules affect very few homes, and the real constraint is the clay under the foundations, which a good engineer can design around.