‘Listed buildings’ are older properties which have been classified as having a special historical or architectural significance. They have a protected status, with a number of laws in place to protect their internal and external characteristics. Unfortunately, this can make it difficult to gain permission for making alterations to a listed building, such as if you wanted to replace the old timber windows.
When it comes to window replacements, your most reliable tradesman will always be a qualified local glazier. A specialist will be able to handle older glass with utmost care and should also be able to give you advice on finding a replacement that will stick with the original character of your property. You may also be required to make a ‘sympathetic replacement’ in the style of your older windows; If this is the case, you may need to speak to a qualified carpenter about properly designing the replacements.
There are three kinds of ‘listed buildings’, with the different types marking their level of protection. Grade I buildings are believed to have exceptional interest and can be the most difficult to alter. Granting permission for a job that will change the character of a grade I property can require a careful consultation between the Planning Department, English Heritage and the Secretary of State! Grade II* buildings are marked as having above-special interest, while grade II buildings are of a special interest. Grade II buildings often have mostly unaltered exteriors, but will have an interior of a special interest.
In terms of historic significance, windows might seem like an odd sticking point. However, older glass can be highly valuable: before glass was mass produced it was handmade, and the result was a very fine and delicate material that only the wealthiest at the time could even afford. This style of glass is quite rare nowadays, and it can commonly be seen as a vital part of an older building’s historic character.
If you want to replace a window in a listed property, your first move should be to contact your local authority’s Conservation Officer. They will be able to discuss the protected status of your property, as well as what alterations will be acceptable. Groups like Historic England also keep lists of specialist tradesmen which they may be able to recommend for your project.
As a rule, the groups in charge of listed properties prefer repairs to replacements. However, they can occasionally grant permission for a sympathetic replacement, which will involve fitting a new window that has the same characteristics as the old. Sympathetic replacements are typically made with the same materials and designs as the originals.
Because most older windows have timber frames, it may be necessary to speak to a carpenter about making a sympathetic replacement. Depending on the amount of detail required, you may need to find a niche specialist. Your window can then be fitted by a competent local glazier.
One thing that you can be fairly certain of is that you will not be able to get permission to alter the structure of your listed property. Because of this, you will not be able to replace your old windows with alternatives which would require changes to the structure of your roof.
If the reason that you want to replace your window is to do with energy efficiency, there are other alternatives that you can still consider if you fail to gain permission for your project.
Wooden shutter installation can provide an effective layer of insulation for your windows. Shutters can also be installed inside a property so as not to alter its external appearance. Similarly, you could improve your home’s energy efficiency by installing thick curtains or insulated blinds.
Another option is ‘secondary glazing’. This is a slimline window layer that can be attached to an existing window pane to reduce the amount of heat escaping through it.