Decaying wood can be a big problem when it comes to sash windows and homeowners need to be aware. To check the window frames, take a flat blade screwdriver and tap the frame, moving all the way around the window. If the screwdriver can easily be pushed into the wood, it’s a good sign that it has begun to soften and decay. At this stage, you’ll need to consider replacement.
Sash windows are at the centre of many period properties and a number of factors need to be considered when replacing sash windows as part of the refurbishment of your home.
How often should wooden windows be replaced?
There is no standard time frame on how often a wooden window should be replaced, but many original timber sash windows have lasted a hundred years with regular maintenance. With regular maintenance, the average lifespan for a high quality, timber window is 72 years.
Salvage the timber windows where possible
In cases where sash window repairs can be undertaken, it may be more suitable, and more cost-effective, to salvage the windows rather than simply replacing them. Sash window repair will often involve draught-proofing, servicing the pulleys and balancing the sashes.
Getting the proportions right
Sash windows conformed to different proportions over the centuries, and getting this correct to reflect the period of your home is essential. As an example, Georgian sash windows mirrored the Classical ‘Golden ratio’ (1: 1.618), which was made up of ‘six over six’ panes as well as slim, elegant glazing bars and meeting rails.
Double glazing options
While double glazing sash windows will help to improve their overall energy-efficiency, it will change the overall look of your sash windows meaning that it often won’t be approved if you live in a listed building. Alternatives can include secondary double glazing for sash windows, or using Pilkington Spacia glass, which at a thickness of a single (6mm) glazed window offers the thermal performance of double glazing.
Replacement sash windows
If your wooden sash windows need replaced then it is worth investing in new timber windows. uPVC windows might last for twenty years, but when the materials start to fade and discolour, the whole window will need replacing. In comparison, timber sash windows might need more maintenance, but if you do the necessary work, they will last for decades longer. By using a more durable timber like AccoyaTM you can also reduce how often maintenance is required.
If your sash windows need to be replaced, this should ideally be on a like for like basis so that the character of a building is preserved. There are a number of specialist sash window companies, including The Sash Window Workshop, who are able to provide this service.
As sash windows can significantly contribute to the character of a period home, certain restrictions on their modification can apply when homes are located in conservation areas.
Permitted Development rights normally mean that homeowners will be able to carry out a number of changes to their home without the need to seek out planning permission first.
However, local authorities are able to adopt a special planning regulation known as an Article 4 Direction, which they may utilise in certain locations, such as some conservation areas. This will mean that Permitted Development rights are suspended for specific classes which could include the replacement of windows and doors. If this is the case for your home, you will need to apply for planning permission before you can replace your sliding timber sash windows.