Windows explained, and how they fail

How windows and sealed units are made and how they fail, explained by a window fitter: seals, air gaps, glass, frames and finishes.

• Sealed units explainedSealed units are the glass in double glazing: how they are built, why they mist, whether they hold a vacuum, and where to read more about each problem.
• Sealed units in wooden framesWhy sealed units in wooden frames mist up early, how double glazed units should be fitted so water can drain away, and what to ask before you replace one.
• Double glazing air gapWhat the double glazing air gap does, why a wider gap isn't always better, and what to ask a fitter about instead: gas fill, coating and energy rating.
• Toe and heel window glazingWhat toe and heel glazing is, why a heavy window or door sash drops without it, how to check yours, and what to ask your fitter to do.
• Pinking in uPVC windowsPinking in uPVC is a rare pink or brown discolouration of white frames. What it looks like, what I think causes it, and what to do if your frames have it.
• Exploding double glazingWhy exploding double glazing happens: heat and cold put stress on the glass, and what you can change at home to cut the risk of a cracked unit.
• Window sealant: which silicone to useWhich window sealant to use: why silicone joints fail, how neutral cure and acetoxy differ, what the markings on the tube mean, and what to ask your fitter.
• Dummy sash windowsWhat dummy sash windows are, why firms offer them, and the case for and against: looks, security, light and cost, with questions to ask before you order.
• Bay window calculator and surveyA bay window calculator that turns inside measurements into the width and angle of each angled window, with the survey method a fitter uses to prove a bay.
• Velux window repairs: what can be fixedVelux window repairs: how to find the real cause of a leak, condensation or draught, what can be fixed without replacing the window, and what to ask.
• Wood grain effect uPVC windowsWhat wood grain effect uPVC is, how the foil finish is applied, what it costs you in looks and upkeep, and what to ask before you choose a colour.
• Window beading and securityWindow beading and security: why bead and lock type matter more than sales talk, how to tell a security bead from a knock-in bead, and what to ask.
• Brewster's fringes in double glazingBrewster's fringes are faint grey or coloured bands in double glazing, caused by light, not a failed seal. How to recognise them and what to do.

VELUX is a trade mark of its owner. The Window Man is independent and is not affiliated with, sponsored or endorsed by any manufacturer. We name brands only to help you compare like with like; see how we make money.