When plastic is not so fantastic; UPVC windows do not last forever and have problems of their own, warns Peter Fall.
HANDS up if you don't have a plastic window! Sorry, I should have said uPVC framed window, but I'm sure most home owners refer to them as plastic windows.
Now there's not much wrong with uPVC window frames. But contrary to most people's opinion, they can give you problems and don't last for ever. UPVC does degrade in sunlight over the years, not as bad as 15 years ago when the white ones would turn yellow after about 10 years, but they do become brittle. Most of the catches are fixed by self-tapping screws which pull out of their holes as the plastic hardens. Securely replacing a screw that has pulled out can be tricky. An inadequately fixed catch can reduce the security of your home.
All modern windows should have trickle vents that let in air to replace the leaks we used to get from our older draughty windows. It may seem silly to create a draught when the one thing you wanted was to stop the draughts, but we need a flow of fresh air to live and safely occupy our homes.
The vent should be capable of a variable width of opening but the small plastic pivots they need to operate become brittle, you can guarantee, where they have been used in the past, they will have broken off after 10 years or so. I frequently inspect houses where the trickle vent slots are stuffed up with kitchen roll and Sellotaped over.
Many uPVC windows rely on neoprene or synthetic brush draught strips around each of the openings. Correctly fitted, they are very effective but over the years they become damaged or even worse pulled out by an over enthusiastic occupier desperate to get the window to close. Rarely does an owner replace these strips so the windows leak even more air and start to rattle in high winds.
My biggest grump is none of these windows seem to have a long enough window cill. The outside cill should shed any water running down the window, away from the wall beneath.
Over the years it has been felt that at least a 25mm (1in) projection is sufficient to cause the water to drip away from the wall and on to the ground. UPVC window cills will do this but because the cill is not very wide, the frame is positioned at the front of the window opening.
Apart from looking a bit strange it can also expose the house to dampness from driving rain.
Let's go back to days of old when windows were set back at least 100mm (4in) from the face of the wall. This meant that any driving rain had to soak back not just the width of the window frame but also the projecting 100mm before it showed up on the inside. It took a long period of heavy driving rain before the wall inside became damp.
Similarly with the more recent cavity walls, here the builder fits a vertical damp proof course at the window opening where he connects the inside leaf of wall to the outside leaf.
But if you set the window frame at the front of the opening then it will be in front of the damp proof course, so the dampness soaks back round behind the frame and the plasterwork in the opening becomes wet.
If only the manufacturers and installers had used a wider window cill, just another 50mm (2in) wider would do, then this problem wouldn't occur.
? Peter Fall, a chartered building surveyor and dispute resolver, is a former president of the Royal Institution of Chartered Surveyors, tel: 0191 284 3467 or go to www.peterfall.com