Repairing Windows in an Older Home
You should try to retain your historic windows wherever possible using careful matching repair. Their complete replacement should be a last resort and is rarely necessary.
If you want to make repairs to your windows you may need permission and should seek advice if your home is listed or in a conservation area (see Who Do I Contact?).
Properly maintained, old timber windows can enjoy extremely long lives. They were usually made of high-quality durable timber and some are still in use after as many as 250 years.
Repairing timber windows
It is usually significantly cheaper to repair timber windows than to replace them. Careful repair is always preferable to new work as it will also retain the historic fabric of your home. It is very rare that a window is totally beyond repair. For more on historic windows see the Making Changes section.
If the energy efficiency of your windows is an issue this can be improved dramatically at the same time - see our Saving Energy pages for more details.
Use the best methods and materials
There is a widely held perception that repairs, particularly of external softwood joinery, are short lived and not as good as replacement. This is not the case. The key is to start with the right plans and materials. Poorly thought-out repairs, or ones using unsuitable materials, will quickly fail.
You should aim to limit any work to the minimum required to fix the problem. Wherever possible, repairs to window frames should be carried out in situ, particularly when the frame is built in and cannot be easily removed without damaging either the window or the surrounding wall.
Sash windows and casements can usually be removed without damage for repair either on site or in a joiner's workshop. Sash cords can be easily replaced without professional help, but you may need advice from a joiner or glazier when it comes to replacing parts of the frame or glass.
If several windows have to be dismantled in the course of repair, don’t forget to mark and record all the components and where they fit in before beginning the work as there are bound to be tiny variations.
Metal windows can suffer from surface rust, distortion, excessive build-up of paint, and failed hinges and fittings. Rust expands up to seven times the volume of unoxidised metal, so corrosion can often look much worse than it really is. Even windows that appear in a very bad state at first sight can often be repaired.
Repairing metal windows
Traditional metal windows can often be economically repaired and draught-proofed, avoiding the need for total replacement. Heavy rust and paint can be removed by acid pickling or flame cleaning. There are several firms specialising in this kind of work.
Any necessary repairs to wrought iron or steel windows can be made by a metalworker welding in replacement sections. Cast-iron windows cannot be welded because they tend to crack when heated, but they can be repaired using a technique known as 'cold stitching'.
Rust does not mean replacement is necessary
Renovation can be done either on site, using wire brushes, files, and small grinders to remove rust and scales, or in a factory, where the windows can be grit- or shot-blasted and galvanised (or, in the case of more fragile specimens, zinc-sprayed). What might look thoroughly rusted and unusable may have decades of life left in it. You may be able to remove the rust yourself, but it’s best to seek advice from a professional specialising in metal windows to avoid further damage from over-scrubbing.
Different types of metal in windows
The best way of repairing a metal window will depend on the type of metal used. Ferrous metals will have different problems to non-ferrous metals such as bronze and aluminium, and within the ferrous metals wrought iron will need to be treated quite differently to cast iron or steel.
The manner of production is also extremely important: for example early steel windows (before the mid-1950s) were not galvanised and so are particularly prone to corrosion, which often appears as rusting of the horizontal glazing bars and the bottom rails. If in doubt, seek professional advice before attempting to clean up your metal windows.
Also of interest...
Windows contribute to the character of older houses. It’s important to understand your windows before deciding on work to them.
There are various ways you can make your sash windows more energy efficient, from having them repaired to installing secondary glazing.