Timber windows on Grade I, Grade II* and Grade II listed buildings cannot be altered in any way without planning permission, or ‘Listed Building Consent‘, and it is against the law to do so.

It is possible to get planning permission to replace or restore windows on listed buildings, but any listed building planning application needs to be treated sensitively. Application forms can be found on your local authority website. 

Planning officers quite rightly think of listed buildings as valuable architectural antiques, and are looking for evidence that you respect and appreciate the value of preserving the inherent character of the building as far as possible.

Here are some key points to consider when making a listed planning application for windows:

1. Restored or replacement windows?

Sash windows on Grade II Listed buildingIf your property has the original period windows with the original glass in them, it is unlikely that you’ll get planning permission to change the original windows completely, if they’re in a restorable condition.

However careful restoration and draught-proofing would be more likely to be approved, which will help to retain the look and character of your property while being more cost-effective than full replacement.

2. Planning applications – Be honest

If your property has, for example, two original windows in reasonable condition, it will help your case to be honest from the start and say that two could be saved. Don’t just say they’re all bad and all need replacing. Or alternatively suggest that the two could possibly be saved, but in this case you’d like to change them all with a sensitive replacement.

3. Planning applications – Build a solid case

 If you’re asking to fully replace your windows, you need a ‘justifiable cause’ why you’d like to replace them.

This justifiable cause could be that the windows are beyond economical repair. For example the rails have rotted away, or there is significant rot and decay. In this situation replacement rather than restoration could be the best long-term solution for the property.

Another justifiable cause is if the windows have already been replaced, but in an inauthentic or inappropriate way. This could involve not using the original material, or using the wrong glazing bars for example, so you could suggest that they could be changed back to something closer to the original windows.

4. Use listed windows experts

Specialist listed window providers such as Timbawood are able to provide exact-match heritage windows that will stay faithful to the look of the property and any neighbouring properties. Mention you are using a specialist window restoration company with experience of working with sensitive buildings to help your case.

Specialist materials such as restoration glass can be used – which has the slightly uneven look of period glass compared to the modern flat look – and the windows can be hand puttied and hand painted, and fitted with slimline double glazing that looks like single glazing – to complete the period look.

5. Provide photos and CAD drawings

CAD drawings casement windows

Example CAD drawing

Provide photographic evidence of what your windows look like now, and ask your window provider for a set of CAD drawings – one as the windows look now, and the other as they will look after the replacement. This should show the planning officers how closely the replacements will match the originals.

Remember, every case is different and there is no guarantee that your planning application will be approved.

Good luck!

Timbawood specialise in custom-built sash windows, casement windows and doors for listed buildings and offer a range of draught-proofing and glazing options, including restoration glass and our ‘Timbalite’ slimline double glazing that looks just like single glazing. Get in touch with us if you’d like to find out more.