Question 1

How long do double glazed sealed units last?

Accepted Answer

When it comes to how long double glazed sealed units (the glass inside the window) last, a lot of it is down to the quality of the glass and the environment that your windows sit in. It’s not uncommon for your window frames themselves (especially if they are uPVC) to last longer than your sealed units. Sealed units are called that because they’re two panes of glass sealed together with an air gap in between. They use what’s called a ‘perimeter seal’ to protect the air gap between the panes, and is usually made of butyl mastic which retains a desiccant within a perforated metallic spacer bar. The desiccant’s job is to absorb any moisture which finds its way into the air gap to stop your window from misting up on the inside. When a sealed unit fails, or is ‘blown’, it’s usually because moisture builds up around the seal and causes it to fail. Sealed units won’t last forever, so you will eventually end up with condensation inside the panes of your double glazing, but in an ideal environment your double glazed sealed units could last up to 30 years, with some manufacturers claiming as long as 40 years. But they do require a bit of maintenance and the position of your windows will also make a difference as to how long they last. There are a few things that determine how long a sealed unit will last: Climate - If your window faces south, it will be subject to direct sunlight for a lot of the day. This tends to cause the sealed unit to fail more quickly – a south-facing window may last between 10-25 years. This is because the spacer bars will twist as the temperature rises and causes the adhesive holding them together to eventually fail. Moisture - Windows in kitchens and bathrooms tend to fail more quickly because they come into contact with moisture more often. For example, if water gets on your windowsill when you shower, the seal around the glass will come loose more quickly if it’s constantly wet. When you replace the sealed units in your windows or get completely new double glazing, make sure you choose an installer that uses quality products and will take all the steps to ensure that your sealed units are kept away from moisture as much as possible.

Question 2

Do I need toughened glass in my windows?

Accepted Answer

Whether you need toughened glass in your windows depends on where the windows are in your home or business. Toughened glass is sometimes referred to as tempered or safety glass, and it just means it’s stronger than the standard glass that’s usually offered with double glazed windows. So how do you know if you need it?

Toughened glass is useful in areas of your home where you might come into contact with the windows if you were to trip and fall. If you put your hands out to steady yourself on standard glass the chances are it would break into large sharp pieces with jagged edges. Of course, this means that you could seriously cut yourself if this were to happen. With toughened glass, the structure of the glass is changed so that if it breaks it shatters into lots of tiny pieces, minimising the risk to you if you were to fall on it.

You might want to use toughened glass in patio doors, low windows or frames next to doors. It just means that you will be safer if the unlikely happens and you or a family member falls through the glass. There are certain requirements through Building Regulations with windows at a certain level, but any reputable window installer should be able to go through these with you if you need to replace your windows with toughened glass. The regulations will only apply to new windows – there's no need to switch your windows to toughened glass early, but when you do come to replace them you’ll need to make sure they meet the standard.

Question 3

How to fix a cracked glass window?

Accepted Answer

You can end up with a cracked glass window in a few ways. The most common one is when a rogue stone in the lawnmower hits the window or someone’s cricket or tennis game goes wrong and you end up with a ball through the window. Youi often end up with a ‘bullseye’ type crack that expands out from the point of impact. You can also get pressure and stress cracks from intense fluctuations in pressure and temperature. Unfortunately, there’s no way you can permanently fix cracked windows without replacing the entire sealed unit. An installer can replace a cracked glass window in less than an hour simply by taking out the sealed unit (the two panes of glass in double glazed windows) and replacing it with a new one. It costs an average of £110, but you could try to do it yourself for around £55. But what if you can’t get an installer to fix your window straight away? There is a DIY method you could try. As a temporary fix for your glass window, you can use a solvent-based adhesive like epoxy which will keep the glass intact and prevent further damage. You’ll also need: Washing up liquid Glass cleaner A lint-free cloth or rag A putty knife A paper plate Acetone First, you’ll want to clean the glass using the washing up liquid and a damp cloth to remove any dust or oils. Leave it for a few minutes to dry, then create a mixture of epoxy by combining the hardener and the resin and stirring it on a paper plate. Using the putty knife, spread the mixture on the cracks, making sure you press gently to fill them. Leave it for at least 5 minutes to dry, then get rid of any excess by using some acetone on a dry cloth. Clean the window using some glass cleaner and another dry cloth, and you should have a temporary fix!

Question 4

Can the glass in a double glazed window be replaced?

Accepted Answer

Yes, the glass in a double glazed window can be replaced. The glass in a window, or sealed unit to use its proper name, is not permanently attached to your window frames so if it gets damaged but your frames are still intact, there’s no need to replace the whole window. The glass in your double glazed window might need to be replaced due to: Impact from a stone or other object smashing the glass in a ‘bullseye’ effect The result of a break-in Extreme weather or changes in pressure causing a crack The sealed unit being ‘blown’, meaning that it’s no longer energy efficient due to air leaking out A lot of window installers will replace the glass in your double glazing for you, but you might need to get quotes from specialist glaziers too. Glaziers deal purely with the glass in windows rather than installing entire frames. It won’t take a professional very long to replace the glass in your window. They will remove the beading from around the window with a pallet knife or chisel, leaving the top one until last to keep the sealed unit stable. Then, they simply lift out the glass carefully and will discuss with you whether the removal of the old sealed unit is included in their quote. Next, they will brush away any dust and debris that’s made its way into the frame and place spacers at the bottom. They will then lift the new glass into the frame, making sure it’s completely square. When they’re happy, they’ll remove the spacers and replace the beading back in reverse order. You’ll notice the replacement glass in your new window straight away as draughts should be eliminated and you’ll be able to see clearly again!

Avg. price low	Avg. price low £57
Avg. price	Avg. price £75
Avg. price high	Avg. price high £87

	Labour cost	£53
	Material cost	£19
	Waste removal	£4

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