Mostly yes, because Horley has very little to be precious about. Hardly any of it is listed. Three pockets are protected, and the rest is post-war housing nobody is fighting to preserve. The neighbours put in applications all the time. The planning officer has seen your kitchen extension before, several hundred times.
Historic England lists 57 buildings in and around Horley. One is Grade I, none are Grade II*, and the other 56 are Grade II. Listing covers the whole building, inside and out, so even modest changes to a listed home need listed building consent on top of any planning permission, and replacing a window with whatever the builder had in the van is how owners end up in correspondence they did not want. For a town of this size, 57 is a short list. The odds that the house you are viewing is on it are slim, but the check takes minutes and the surprise lasts years.
There are 3 conservation areas: one covering the historic core of Horley itself, one around Church Road and one around Massetts Road. Inside them, the council takes a closer interest in anything visible from the street, from extensions to materials to demolition, and changes that would sail through elsewhere may need a proper application. Buyers who fell for the older houses on those streets should expect the planners to have fallen for them first.
Two scheduled monuments sit within the wider area, including the moated site of Thunderfield Castle to the east of town. Scheduling is the strictest protection there is, and it matters mainly to anyone whose garden or land runs up against one.
The neighbours are not waiting for permission to be easy. The council logged 1,162 planning applications across the area between April 2024 and June 2026, and 510 of them came in the last twelve months. That is a town that alters its homes as a matter of routine: loft conversions, rear extensions, the garage that finally became a room. Volume is not approval, and those figures say nothing about how many were granted, but they do say nobody here is afraid of the form.
In practice, most of Horley is ordinary housing outside any designation, where smaller extensions and alterations often fall under permitted development and need no application at all. Once a house is listed, in a conservation area or next to a scheduled monument, the rules tighten and assumptions stop being safe. Check the exact address against the council's constraints before costing the build, because the architect's drawings are cheaper to change than the planning history.
Horley sits in the middle for freedom to alter a home: loose across most of the town, properly tight on a handful of old streets. Buy on the right side of the conservation line and the only thing standing between you and the extension is the quote.