Repairing Windows in an Older Home

Try to retain your historic windows wherever possible by having them repaired rather than renewed. Complete replacement should be a last resort and is rarely necessary. If repair is beyond the skills of a good joiner or metal worker, an accurate copy should be made.

If your house is listed or in a conservation area with an Article 4 Direction (which restricts work you can normally do without planning permission) you are likely to require consent to make any alterations to windows, whereas like-for-like repairs do not usually require consent. If in doubt consult your local planning authority before carrying out any work.

Repairing timber windows

Properly maintained, historic timber windows can last indefinitely as they were usually made of high-quality durable timber.

It is usually significantly cheaper to repair timber windows than to replace them. Careful repair is preferable to new work as it will retain the historic fabric of your home.

For more on historic windows see the Making Changes section. 

If you would like to improve the energy efficiency of your windows this can often be incorporated as part of the repair work - see our Saving Energy pages for more details. 

Use the best methods and materials

There is a widely held view that repairs, particularly of external softwood windows, are short lived and not as good as new replacement windows. This need not be the case if you use an experienced joiner and the right 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.

The individual sashes from sash windows and casement windows can usually be removed for repair without damage. If several windows have to be dismantled in the course of repair, it is good practice to mark and record all the components and where they fit in before beginning the work as there are bound to be tiny variations.

Repairing metal windows

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 sound metal, so corrosion can often look much worse than it really is.

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 zinc-sprayed.

Different types of metal used for windows

The best way of repairing a metal window will depend on the type of metal used in its construction. 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 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.

Read more about conservation of metal windows: Historic steel-framed windows – article by Sophie Godfraind in volume 162 of 'Context', the Journal of the Institute of Historic Building Conservation, published by Cathedral Communications Ltd in November 2019.

Further information

For more information on repairs to windows see our guidance:

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