Until 1 April 2002, replacing a window was largely a matter between the owner and the installer. From that date the position changed. With the revised Part L of the Building Regulations in force, replacement windows and glazed doors in existing buildings had to meet the Building Regulations, including new standards for energy efficiency. The change affected anyone who owned a house, managed a block or was planning works to a period building.
How to show compliance
There are two routes:
- use an installer registered with FENSA, the scheme set up by the glazing industry, who can certify that the work complies without a separate application to building control; or
- give notice to the local authority building control service before the work starts, so that it can be inspected and approved.
Either way, you should end up with a certificate. Keep it safe, because a buyer’s solicitor or a future surveyor is likely to ask for it.
What the rules cover
The new windows must meet thermal performance standards, which in practice usually means sealed double glazed units. The work must also not make the building worse in other respects, for example by reducing the ventilation the rooms had before. A good specification deals with these points at the outset rather than on the day of installation.
Listed buildings and conservation areas
The Building Regulations do not replace planning controls. Changing the windows of a listed building normally needs listed building consent, and replacing original timber sashes or casements with modern units is often resisted. In conservation areas, the council may have removed the usual freedom to change the windows of houses, and flats generally need planning permission for any change in appearance. In historic buildings, the aim of saving energy has to be balanced against keeping the character of the building, and repairing original windows, with draught stripping and secondary glazing, can be a better answer than replacement. Discuss the options with the conservation officer and building control before ordering anything.
Our advice
Before replacing windows, check whether the building is listed or in a conservation area, decide whether repair is possible, and agree a clear specification. Then choose the approval route and keep the paperwork.
See our Planning and Heritage and Building Surveys and Defect Diagnosis services, and how we later secured two listed building consents within one listed building.