Conservation areas

Changing windows

If you want to alter or replace a window in a conservation area, you may need to apply for prior approval and listed building consent.

When prior approval is needed

You must apply for a determination on prior approval if:

  • the window is on the front (principal) elevation, or
  • the window is on a side elevation that faces a road, and
  • the new window is not the same, or substantially the same, as the one being replaced

We will assess whether the new window is the same in terms of:

  • how it opens and closes
  • the number, layout and colour of the panes
  • the size and colour of the frame or any astragal bars

When prior approval is not needed

You do not need prior approval if:

  • the window is not on the front or a side that faces a road, and
  • there is no Article 4 Direction removing permitted development rights in your area

See if an Article 4 Direction applies to your property

Design requirements

The new window must match the age and style of the building. We will not approve designs that harm the character or appearance of the conservation area.

For example, if the building has traditional sash and case windows on the front or side, we expect the replacement to match that style.

Apply for prior approval

Page last modified: 23 January 2026