What can go wrong with DIY double glazing?

An Englishman’s home is his castle. We all take pride in our homes and (some of us) love nothing more than rolling up our sleeves and getting stuck in to a project to improve the home we live in and love. If you are one of life’s handymen or handywomen there’s often the temptation to take on jobs that you feel you will be capable of doing – especially when the Easter Bank holidays are around the corner!

Here at Finesse – we are more than happy to manufacture windows & doors to your specification and dimensions for you to then install yourself. However, there’s a few things that we like to point out to people before they take the plunge and decide to take on a DIY double glazing project.

Challenge 1 – the survey. The first thing you need to be aware of is that there is no such thing as a standard size, off-the-shelf window or door. Every window or door is manufactured from scratch and each one is different in terms of its dimensions and configuration. If you are tackling your UPVC windows as a DIY project you will be responsible to provide accurate measurements. Therefore the first thing to do is to get an accurate survey of the windows to be made.

One of the easiest mistakes to make is to assume that measuring the window from the inside is adequate – unfortunately it isn’t always. The size of the UPVC window from the inside will differ from the size of the UPVC window outside. This is mainly due to the fact that the inside of the window will often be plastered and the true size of the window is regularly hidden. Unfortunately the answer isn’t always to measure the window from the outside either because the outside dimensions are regularly hidden by external render. Bear in mind too that if you have to measure a window from the outside you are going to need some long ladders (make sure somebody is at the foot of them to keep them steady). Often, the outside of an upstairs window is hard to get to – because there are often ground level obstacles which get in the way – e.g. bushes, porches, conservatories, bay windows with sloping roofs are all things that make surveying a window accurately a real challenge.

The reason why it is crucial to get accurate dimensions at survey is threefold. A badly fitting UPVC window is draughty, unsightly and unsupportive. Draughty, because there is a chance that air will be able to pass around the edges of the badly fitting window and into your home. Unsightly, because the only way to fill in the gaps around the window will be to use excessive silicone sealant which looks aesthetically poor. Unsupportive, because a badly fitting window risks the chance of brickwork dropping above the installation (we will discuss the use of brickwork lintols in future articles).

Hopefully this article has been useful to introduce some basic concepts which will need to be considered before you contemplate embarking on a DIY UPVC window project.