Yes, most likely, unless you've bought one of the listed ones. Sixty-odd buildings are listed. There is no conservation area. The whole village sits inside protected landscape. Ticehurst lets most owners build; it just insists they ask nicely first.
There are 65 listed buildings in the area: none at grade I, 1 at grade II* and 64 at grade II. Listing covers the whole building, inside and out, so on a listed home even internal changes such as removing a wall, replacing windows or reworking a staircase need listed building consent on top of any planning permission. Grade II is the most common grade and still carries the same legal requirement, and carrying out works without consent is a criminal matter, not a paperwork slip. If the house is one of the 65, the question isn't whether you can change it but how long the conversation with the conservation officer takes.
Owners here clearly don't let that stop them. Between March 2024 and June 2026, 427 planning applications were lodged for the area, 181 of them in the last twelve months. For a village this size, that is a steady stream of people drawing garden rooms, loft conversions and rear extensions on the backs of envelopes, and it is live evidence that altering a home here is normal, not exceptional.
For the houses that aren't listed, the rules are more forgiving. There is no conservation area recorded, which removes one common layer of control. But all of Ticehurst lies within the High Weald Area of Outstanding Natural Beauty, and that designation narrows some of the permitted development rights an owner in an ordinary suburb would take for granted, so a project that needs no application in a town might need one here. The sensible sequence is to check whether the house is listed, check what permitted development still applies to it inside the protected landscape, and ask the council for pre-application advice before paying an architect for anything more than a sketch. Buyers who assume the estate agent's "scope to extend" line came with a planning officer's blessing tend to find out otherwise at the drawings stage.
Freedom to extend in Ticehurst is middling: the 65 listed homes are tightly held, the rest face the extra caution of protected countryside, and plenty of owners still get their extension built by doing it in the right order.