In most of Markyate you can extend a house without much fuss, but the old High Street is a different matter. The village has a fair number of listed buildings. Nearly all are at the ordinary grade. One conservation area covers the historic core. The post-war streets behind it are where extensions get built.
Markyate has 45 listed buildings: none at Grade I, two at Grade II* and 43 at Grade II. Listing covers the whole building, inside and out, so anything that changes its character, from a rear extension to a replacement window, needs listed building consent from the council on top of any planning permission. A village with a priory site, a country house and a past as a coaching stop has managed to collect not one Grade I, which is good news for anyone who owns one of the 45.
There is one conservation area, named after the village. Inside it, Dacorum Borough Council can control changes that would be allowed without permission elsewhere, from demolition to work on frontages, and it expects new work to fit the street. Dacorum's conservation area map and the national listing register both show whether a particular house is covered, and either takes a few minutes to check.
People here alter their homes constantly. Planning records for the area show 1,655 applications between April 2024 and June 2026, and 750 in the last twelve months alone. That is a lot of loft conversions, side extensions and garden rooms going through the system, and it shows the council is used to dealing with them.
Outside the conservation area, and away from the listed buildings, most of Markyate is ordinary housing, and a lot of it went up after the war in the gap between the High Street and the bypass. On those streets a modest rear extension or loft conversion can often go ahead under permitted development, the national rules that allow some work without a full planning application, subject to their size limits. A semi on a post-war close and a cottage on the High Street can be a hundred yards apart and still sit under completely different rules, which is the thing worth knowing before setting a budget.
Freedom to extend in Markyate is middling: easy on the newer streets, slow and careful on the old High Street, and the house's address decides which of the two you get.