Yes, you can, but expect to justify it. There are more than a thousand listed buildings across the area. There are twenty-nine conservation areas. There are prehistoric barrows in the fields and clay under the lawn that shifts with the weather. People still build extensions here, but they do it with paperwork and a lot of patience.
The Pulborough area holds 1,066 listed buildings. Thirty are Grade I, 36 are Grade II* and 1,000 are Grade II. Listing covers the whole building, inside and out, so on a listed house you need listed building consent for almost anything that changes its character, from the windows to the internal walls. Carrying out that work without consent is a criminal offence, not an administrative slip. Most of the listed stock is Grade II, which means plenty of ordinary-looking cottages are listed, not only the country houses.
There are 29 conservation areas across the area, two of them in Pulborough itself at Church Place and Lower Street. Inside a conservation area the council looks harder at anything visible from the street, and some changes that would go ahead without an application elsewhere need a planning application here. Removing trees, altering front elevations and some demolition all come under closer control.
The area also has 71 scheduled monuments, the strictest level of protection, covering barrows, Roman sites and Pulborough Park's motte and bailey castle. Unless your land borders one, these are background, but if it does, the rules get considerably stricter.
The neighbours are not deterred. Planning records show 1,492 applications between April 2024 and June 2026, and 681 in the last twelve months. Those are counts of applications, not approvals, but they show that plenty of people here keep trying to change their homes.
The ground is part of the answer too. The British Geological Survey rates shrink-swell clay at up to class 3 across the area, and about 79% of postcodes reach that class. Clay soils like this swell when wet and shrink when dry, which affects how deep an extension's foundations need to go and how close it can sit to trees. It is a reason to get a structural engineer involved early, not a reason to give up.
Three listed buildings in the area are on Historic England's Heritage at Risk register. These are buildings in poor condition. Their repair may qualify for grant support and will certainly draw close scrutiny, but they are no concern to the buyer of an ordinary house down the road.
Before assuming you can build under permitted development, check three things: whether the house is listed, whether it sits in a conservation area and whether any restrictions apply to the specific address. Outside those, the standard permitted development rules apply. Inside them, assume you need consent until the council tells you otherwise, and ask before the builders arrive, not after.
Your freedom to change a home here is poor. Extensions do get built, but they come more slowly and cost more than buyers expect, so price the delay in before you offer.