Historic Building Conservation

Want to change or repair the windows in your listed property?

In listed buildings planning permission is required for works affecting windows and external doors, including ‘substantial alteration or replacement’. First, remember that being listed doesn’t mean you can’t change anything, just that it’s expected that you’ll take extra care to get the details right when you do. For windows and doors, Planning need scale drawings of the existing as well as the proposed replacement. Full details of what’s required can be found in the Supplementary Planning Guidance advice note ‘Protection of historic windows and doors’ (April 2018), available on the Planning website.

The law states that single-glazing in listed buildings must be retained, or replaced like-with-like. But as single glazing is thermally inefficient, and old windows are old and rattly, how can they expect us to save the planet if we can’t change them?

If you have rare or unusual windows that can’t be changed, secondary glazing fitted inside the existing window will reduce heat loss, as will shutters or curtains. Double-glazing can be introduced in listed buildings in some cases though. For instance if you’re replacing an existing plastic window, there’s no reason not to install a modern double-glazed version provided it’s sympathetically designed. Some later 19th or early 20th C frames are even substantial enough to accommodate slim double-glazed units if the rebates are enlarged.

Most of the windows I see in old houses in Jersey were made sometime during the 19th C. Typically they’re sliding sashes – a design first invented in the Low Countries in the 1660s – with multiple panes. The later the window, the fewer the panes – as glass technology developed during the 19th C, single sheets of glass replaced smaller ones.

An experienced historic building professional should be able to advise you on how old and important your windows are and help you decide whether to repair, reglaze or replace.

Painting is the fun bit. Jersey has a tradition of 2 tone windows, with one colour on the sash box and another on the sliding sashes – surely a tradition worth continuing. As for white on a listed or historic building, avoid modern ‘brilliant’ whites, which look a bit stark. Traditional whites were more like off-white today. My tip for a suitable white is Dulux ‘DH’ white (or equivalent).

And finally – if you have that rare Georgian sash with slim ½ inch glazing bars, or an even rarer inward-opening Jersey casement with some blacksmith made iron strap hinges….cherish and enjoy them. There aren’t many left. And lucky you for owning such a lovely bit of history!