Advice on double glazing measurement please.

[rash_decision]

Hi, I was wondering if anyone in the know could give me a bit of advice on how to measure for replacement double glazing please?

A friend who has done this, said just measure the gap and add 10-15mm on the sides, top and bottom, does this sound fair enough?

I have had some astronomical quotes from various companies to replace my windows, whereas a joiner friend reckons I can buy Rehau (spelling??) windows from a local supplier for roughly £300-£350 per window for my size ish. And most joiners around our way charge £50 per window to fit them. Given that my quotes were all around £9k, well, you don’t need to be Einstein to work out it’s a no brainer to try organising this myself. I live in a semi detached, with 6 large windows, and 4 smaller (single?) windows, so should really cost me a good bit less than half my quote price.

Any info, experience or advice on this would be appreciated.

Cheers.

[wolfracesonic]

It just depends on how the windows are going to fit. If they are going to fit in between the external brick, take your width and height measurements and subtract 6mm from each. If they going to fit behind the external brick work that's when you add the 20mm or so. If you try to fit them the last way it will probably involve taking the plaster off the reveals. A little info here https://easyfitwindow.com/measuring_instructions.a...

[Simpo Two]

The tricky part I found was trying to measure the height of the aperture with the old wondow still in place, as the sill obscures what you need to see. I used my best guess but when the windows arrived they were about 5mm too high. Luckily the plastic edge could be planed down!

[rash_decision]

Thanks for the advice. That link to the "how to measure..." is great.

I should have given more info. It's a 1930's semi with cavity wall construction, that originally had wooden sash windows. These have since been replaced by UPVC Double Glazing, fitted from inside, to sit against the external brickwork. Therefore the method of measuring and adding 10-15mm would be applicable in this case.

I'm away from home at the moment, so can't get the tape out, but will be sure to get onto this when I get home.

Have any of you guys done this yourself? I've seen windows being replaced before, and without putting window fitters down, it does look fairly simple? Handy as I am, I'll still be leaving this one for a joiner, or window fitter that's interested in a little 'homer'.

[SAB888]

Get the supplier to measure. Takes any errors away from you. The old sash window reveal construction will affect size.