Yes, you can extend a house in Esher, and a lot of people are doing it. Planning applications run to more than a thousand a year. Four conservation areas cover parts of the town. A fifth of the ground is clay that moves. The council and the soil both have a say.
Esher has 83 listed buildings: 3 at Grade I, 6 at Grade II* and 74 at Grade II. A listed building needs listed building consent for almost any change to its character, inside or out, on top of planning permission. That includes things people think of as maintenance, such as windows, doors and internal walls. At Grade I and II* the bar is higher again. Most of Esher's houses aren't listed, but if yours is, the listing comes before your plans.
Esher's area includes four conservation areas: Esher itself, West End, Weston Green and Claygate Foley Estate. Inside one, the council takes a closer interest in demolition, work to trees and changes that alter how a street looks, and some work that would otherwise go ahead without permission needs an application. Ask the council which conservation area the house is in, if any, and read its appraisal document. That document sets out what the council wants each street to keep looking like.
There are two scheduled monuments in the area, among them The Belvedere at Claremont. Scheduling is the strictest form of heritage protection, and it matters mainly to homes on land next to a monument. Clive of India built Claremont before anyone had invented a planning department, and every Esher homeowner since has had to fill in the forms.
Applications show how much building work is going on. Between April 2024 and July 2026, 2,553 planning applications were made in Esher, 1,074 of them in the last twelve months. That counts applications made, with no record of how many were approved. It does show that in Esher an application is a normal part of owning a house, and the person next door probably has one in too.
The ground needs as much thought as the paperwork. The British Geological Survey puts the highest shrink-swell class in Esher at 3, and about 20% of postcodes reach class 3 or above. Shrink-swell clay expands when wet and shrinks when dry, which moves shallow foundations. For an extension that usually means deeper foundations, a structural engineer's report and some thought about any large trees nearby. It's a known engineering problem with standard solutions, and it adds to the cost.
In practice, a house outside a conservation area and off the listed-building register may be able to do smaller work, such as some rear extensions, under permitted development rights without a full application. Inside a conservation area those rights are narrower, and a listed house needs consent for almost everything. Before relying on permitted development, check that the rights haven't been removed for the specific property, then get a lawful development certificate from the council. A builder's assurance won't protect you if the council disagrees.
Esher gives you about average freedom to extend: outside the protected areas it's mostly straightforward, inside them every change is negotiated, and the clay adds cost either way.