Our guide as Listed building and conservation area specialists.
Changing sash windows or other period windows can trigger planning rules, especially on listed buildings or in protected areas. This guide explains what usually needs consent, and what to do next. Always confirm with your local planning authority before starting work.
Find the closest match to your property and start here.
Usually: No planning permission for like-for-like on houses. Building Regulations may still apply.
Often: Like-for-like may be allowed, but councils can be stricter on street-facing elevations.
Usually: Planning permission required for changes to elevations facing a highway.
Almost always: Listed Building Consent (LBC) required for changes affecting character.
Every Step of the Way
The default approach is repair over replacement
Listed building rules protect historic character. Even small changes can require Listed Building Consent, so the safest route is to agree the approach with the conservation team early.
Keeping the street scene and period proportions
Rules vary by council, but most focus on what is visible from the street and whether replacements match the original style.
When “permitted development” rights are removed
Article 4 areas commonly require planning permission even for changes that would normally be allowed. The goal is almost always to protect original appearance.
Planning Portal: https://www.planningportal.co.uk/
Historic England (listing and guidance): https://historicengland.org.uk/
If you are servicing, repairing and upgrading your existing sliding sash windows, you do not need to contact your local council or conservation officer. If you are replacing your sash windows and live in an article four area or a listed building, you will need to apply for planning permission or listed building consent. The council will usually require photos of the existing, together with section drawings of the existing and proposed together with a specification of materials and finishes.
You only require building regulations if you are replacing the entire sash window and frame with a new window. If you are replacing the sashes within the original frame, building regulations are not required. If your property is a listed building, you do not require building regulations as listed building consent takes precedence and if permitted, your new windows will not need to comply with modern standards. The same may apply if you live in an article four area depending on your local authorities requirements.
If your property comes under an article four directive, it basically means that your development rights are restricted by the local authority to ensure that the properties architectural features are retained and so replacement windows would require a planning application. They often favour repair over replacement however, replacements are often permitted as long as the new windows match the existing design and are manufactured from timber.
If your building is a listed building and you are considering replacing your windows, it is sensible to contact your local conservation officer early in the process to seek pre planning advice and to gain an understanding of what may or may not be permitted. Conservation officers usually prefer repair over replacement but occasionally they will allow replacement windows and so its worth checking.
Yes, you can add double glazing to Period windows and there are some different options available depending on your requirements.
Option 1- Replace your existing sashes within your existing box frames with new Accoya™ replica sashes to match the existing glazed with standard double glazed units with typical U values of 1.2 W/m²K, Slimline Heritage units, individually glazed, double glazed units with typical U values of 1.4 W/m²K or 8.3mm Vacuum glazing with incredible U values of 0.4 W/m²K.
The advantage of replacing the sashes within the existing box frames is that there is no disruption to internal period plasterwork, decorations shutters or panelling. This is a popular choice for many of our customers and building regulations are not required.
Option 2- Replace the entire windows and frames with new Accoya™ windows to match the existing glazed with standard double glazed units with typical U values of 1.2 W/m²K, Slimline Heritage units, individually glazed, with typical U values of 1.4 W/m²K or 8.3mm Vacuum glazing with incredible U values of 0.4 W/m²K.
If your property is listed or within an article 4 area, your choices may be limited to Slimline Heritage double glazing or Vacuum glazing depending on your local authority’s requirements.
This largely depends on your properties status and your local authority’s requirements, together with the condition of your existing windows. If your existing windows are deemed to be beyond repair and actually need replacing, you may well be able to replace your windows with replica double glazed windows to increase your properties insulation.
If you replace your windows without the necessary consent, which may include building regulations, planning approval or listed building consent, there could be complications down the road such as fines, local authority enforcement notices or even a notice to reverse the work. Often these changes come to light when the property is up for sale and solicitors ask for compliance documents.
Replacing windows in a listed building without listed building consent is actually a criminal offence !
Generally speaking no and most people wouldn’t want to but occasionally it has been known that some local authority’s have allowed high end, period looking UPVC windows within conservation areas.
