More about Windows

Misty window
Misty Window

A typical line in a RICS Homebuyers’ report is “Several windows were difficult to open and will require some maintenance and repair, especially to hinges. Some gaskets/seals are detached. Two window units at least have failed and will need replacing. Have a competent contractor quote for all works before exchange.”  

The cost of replacing windows in an average three-bedroom house is around £500 for each window, depending on the contractor you use. So you really need to understand the actual extent of the issues with each and every window, in detail.  

We have talked about the types of window in our previous blog

And as part of inspecting each window, we look at the toughened nature and e-coating present (or absent!) on the glass, as described in that blog. Now we are going to look in more detail at the window frames.

UPVC Frames

The basic UPVC window frame is obviously the most common type. The opening parts are called the casements. We always attempt to open and close them individually, unless they are locked and no key is readily available. On older windows, the casements do not always close correctly into the frame and leave a gap between the casement and frame. This can cause draughts as well as possible security issues.

Strengthened frames

When replacing older windows in (say) bay windows for example, the original window frames often provided support to the masonry above. We have seen many properties where lightweight UPVC windows have replaced these older stronger frames.  This has caused the masonry to sag or the windows to bow; this is very common. Using steel strengthened windows – where a steel frame is pre-moulded in the UPVC to add strength – is a very small extra cost.  However, this is rarely specified as they can be slightly harder to fit and would therefore cost a little more. So in the competitive world of double glazing sales, the sales person will often omit them as an option.

Whilst working for insurance companies on subsidence claims and the instruction says “cracks around the bay”, the first question we ask is when were the windows replaced. Installing window frames that cannot support the masonry adequately is usually the reason for the cracking.

Trickle Vents

Another thing that is often omitted is trickle vents, gaps cut through the frame. Perhaps you are thinking that you are buying “A”rated windows then considering cutting a hole in them!! However, newer windows are often replacing older windows which do allow some levels of ventilation. Modern window openings are normally fitted with a two stage setting. This allows them to be locked for security reasons but still remain slightly open, allowing for essential ventilation of the property.


When the glass is fitted into the casement or fixed part of the frame, a mitred plastic strip is pushed into place to the hold the glass in position. This is called the beading. Older windows were often externally beaded. This is not ideal from a security perspective. An enterprising burglar can use a steel ruler to pop off the beading and remove the glass pane. He can then gain entry inside without making too much noise.

But if the panes do blow (internal misting) then they can only be removed externally – which is costly on a three-storey property. Now windows are internally beaded to make maintenance easier and also to improve security.