Fitting UPVC double-glazed window questions

[diyonly]

Hi everyone,

I'm about to replace one of our damaged bedroom window with a new double-glaze window. Hopefully it'll be here sometime next week. However, to make sure that the installers are not cowboys and are fitting the window correctly, can anyone please:

1. Give me any step-by-step instructions or videos on how they are supposed to install it?
2. How should the stone and brick cavity be filled to stop cold draughts?
3. Can they use kingspan to fill the cavity?

Any help or advice would be much appreciated.

Thanks very much.

 

[martin hill]

No no. Any installer who wants to do a proper job will use a cavity closer. I'd stand and watch as only one window. Make sure that it seated square and level too and not just shoved in. You can usually tell the class of window fitter by the brand of expanding foam he uses lol. Seriously watch as a lot of cowboys just use expanding foam and a couple of frame fixings then a squirt of sealant.And dont believe the BULL about Fensa approved. It just another way of making money.

 

[diyonly]

No no. Any installer who wants to do a proper job will use a cavity closer. I'd stand and watch as only one window. Make sure that it seated square and level too and not just shoved in. You can usually tell the class of window fitter by the brand of expanding foam he uses lol. Seriously watch as a lot of cowboys just use expanding foam and a couple of frame fixings then a squirt of sealant.And dont believe the BULL about Fensa approved. It just another way of making money.

Thank you for your reply Martin. What brand of expanding foams are good/bad? I can stand and watch, but I do need to know what I'm looking out for, hence a step-by-step video or website instructions would be helpful. For example, how do they close random stone and brick cavities? Or how should a window frame be properly attached to the opening?

 

[martin hill]

There are la few ways of window fitting so hard to list. Youtube a good place to look for clips on windows being fitted. You should see them putting the frame in and levelling it up. Fitters have small plastic strips called packers used to true the window frame. If window measured correctly the gap should be no more than 10mm around the edge if brickwork rough. If you have a 100mm cavity proper closers should be used. If you got solid brick walls with no cavity or a small one expanding foam ok with a strip of d.p.c over it.

 

[diyonly]

Thanks very much again Martin. Our house is a random-stone and brick built. As you can imagine, the cavity is not equal and is random in size too, so I assume that due to it being random, expanding foam is the best option?

From the photo below of the current window, you'll notice that the top of the window has no foam at all and a cavity can be seen, yet the bottom seems to be filled. So my question is, does the cavity need to be filled all around (top/bottom/both sides) or just the bottom and sides?

View media item 103482View media item 103481View media item 103480

 

[martin hill]

Have you solid stone lintels above your windows thru both skins of brick/stone ?

 

[diyonly]

I can see the lintels on the outside....not sure if they are sat on both inner and outer walls....why do you ask?

 

[martin hill]

Its just some houses have a large sandstone lintel that goes thru both skins of brick thus no cavity above the window.

 

[diyonly]

Right I understand. But surely if there was a lintel going through both skins, wouldn't we get issues with damp coming through?

Assuming the lintel is not running across both skins, should I tell them to fill the top cavity too?

 

[martin hill]

I have sandstone lintels in my 1900's terrace house and the inside dry as a bone. I would get them to fill it. I bet they will when fitting anyway

 

[diyonly]

Thanks for clarifying this....much appreciate your help Martin.

 

[diyonly]

I forgot to ask, but what type of foam is it that should be used for installing double-glazed windows and filling cavities? Can you provide me with a name or a link please?