Yes, unless you've bought one of the old ones, in which case you ask nicely and then wait. Nearly two hundred buildings in the village are listed. Almost all of them are the everyday Grade II kind, which still means paperwork before you touch anything. The neighbours apply for planning all the time. The post-war semi can have its extension, but the cottage on the corner has to ask first.
Historic England's list puts 194 listed buildings in and around Odiham. One is Grade I, 7 are Grade II* and 186 are Grade II. Listing covers the whole building, inside and out, not only the front the tourists photograph. Any work that affects its character, whether an extension, new windows or a knocked-through wall, needs listed building consent on top of any planning permission. Doing the work without it is a criminal offence, not a matter for a stern letter. If a listed house is on your shortlist, assume every change will need consent until the council tells you otherwise.
People here clearly do extend their homes. Between April 2024 and June 2026, 547 planning applications were lodged in the area, 199 of them in the last twelve months. That number is made up of loft conversions, side extensions and garden rooms. It shows that people keep building, not that every scheme gets through.
In practice, it depends on which house you buy. An unlisted post-war home may be able to use permitted development rights for a modest rear extension or a loft conversion without a full application, within national size limits and subject to the council's prior approval where that applies. A listed building gets no such shortcut. Check the listing status and any local restrictions on the exact address before you commission an architect. Ask the seller what's already been built and whether the consents are in the file.
Your freedom to extend in Odiham is middling. It's easy enough on the newer streets and slow on the listed ones, so find out which kind of house you're buying before you draw up any plans.