Usually, yes, as long as your house isn't one of the old ones. Hardly any buildings are listed. There is one conservation area. The neighbours send in planning applications at a steady pace. Most homes here face ordinary planning rules, not heritage ones.
There are 36 listed buildings in the area. None are Grade I, 4 are Grade II* and 32 are Grade II. Listing covers the whole building, inside and out, so owning one means listed building consent for almost any change that affects its character. That includes internal walls, windows and the fireplace you had big plans for. Buyers who fall for a listed cottage and assume the extension can follow later are the ones who learn the rules from a rejection letter. Check the listing before the offer, not after.
There is one conservation area, Newnham. Inside it, the council has more say over demolition, trees and anything visible from the street, and some works that would be automatic elsewhere need consent. Outside it, the rest of Hook is mostly late twentieth-century housing that sits under standard rules.
The planning register shows Hook has no shortage of ambition. There were 1,805 applications between April 2024 and June 2026, including 729 in the last twelve months. These are plans lodged, not a record of what was approved. Still, the residents here aren't asking whether they can extend. They are asking which builder is free in the spring.
For most homes here, the practical route starts with permitted development: the national rights that allow certain extensions and alterations without a full application, within set size limits. Listed buildings don't get them, and a conservation area narrows them. Houses built on estates can have their rights removed by conditions from the original development, so check the planning history for the specific address. Where there's doubt, a lawful development certificate costs less than an argument with the council.
Freedom to extend in Hook is middling. Most homes are free of heritage rules, but the handful that are listed or in Newnham face a harder road, and estate conditions can surprise everyone else.