TOMMY WALSH SAYS

A good starting point is the original windows – what they are like and what they’re made from – as they would have been designed to complement the building. If yours are not original, talk to neighbours to find out whose windows are.

After that you can make your selection. An important planning issue people often aren’t aware of is that the size of the room governs the size of the glass in the window which should be no less than 10 per cent of the floor area. Modern plastic windows tend to have much heavier frames, mullions and glazing bars to give the windows strength, but these can considerably reduce the amount of natural light.

Take into account when your house was built. Windows in pre-war properties tend to be mostly made from wood or steel (for instance, Crittall windows). These can be replaced with like for like, but with super-thin double glazing, heavier lead weights should be used to replace the old cast-iron type for balance. Post-war buildings tend to have a mish-mash of different design styles, but I’d consider powder-coated aluminium frames with a wooden core and double or triple glazing. These are expensive but durable and virtually maintenance free.

Any south-facing windows will have problems with weathering, particularly strong sunshine. It’s wise to maintain the whole exterior on a regular basis, redecorating every three to five years and making sure that water isn’t getting in. Finally, while there are various new window design concepts, few are more practical and easy to clean than the box frame sash design.