New Windows being fitted - are these gaps too big?

10 Jul 2013
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United Kingdom
Hi all

Currently having new windows fitted and I noticed the gaps in this one look massive.

I know absolutely nothing about window fitting so I don't know if I'm talking rubbish. I know the gaps get filled and sealed then trimmed off but surely this isn't good?

The guy who measured up did seem to do it a bit quickly I thought.

Also it's a 180yr old house so I understand there has to be tolerances considered.

One of the fitters agreed that it's probably ideally about 30-40mm too narrow but that he'd finish it nicely and it'd be all sealed and secure etc and ultimately it makes no difference (they don't seem like they're BSing I don't think) . He also recommended that if I'm concerned I raise it with the company and see about getting a discount as they'd be unlikely to replace it due to cost to them (it's a triple window in the living room).

What do you think? Am I alright here given it's an old wonky cottage or should I complain? The company in question has near flawless reviews on Google.



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I'm a diy'er not an expert, however to me the gaps appear on the large side. I'm not sure if this applies to all installations, however the advice is usually measure at 3 points across the horizontal and vertical, take the smallest of each measurement, deduct 10mm and that's your size. The fact the fitter is sort of agreeing with you is also telling i.e. it's not just your imagination.

Without meaning to hijack your post, we had a similar-ish thing years ago. Mum was getting new windows. The existing (wooden) windows were a frame within a frame. Ahead of the surveyor coming out, I offered to remove small sections of the existing woodwork to enable the surveyor to measure brick to brick. They said don't worry not necessary.

The end result was windows that I reckon could have been 3-4cm wider and longer, I could tell this by the way they had to finish the windows e.g. with additional upvc strips etc. My point was proven when one of the bedroom windows needed replaced by them a year or so later. I asked for it to be re-measured to ensure it filled the cavity better and sure enough, it did.

A bit like my mum's windows, it's not to say they can't make them secure enough in the gaps and finish them nicely, however yes, to me they look a bit on the small side.
Thanks both. The eventual finish looks nice, but I'm concerned now about longevity so I'm going to bring it up. Presumably I'll get offered money off but then do I take it and hope for the best or push for a replacement?

I stayed with the fitters for the rest of the install and they kept talking me through how they're filling the cavities and sealing it all tight etc, then pushing me to go and snag all the windows to see any corrections I wanted (there were a couple with the sealant being messy).

I'm told their boss (the guy who sold them to me) is going to be coming out to check them over as a standard thing also... Which sounds suspect to me as it's quite a drive for him.

Unsure what to do from here!

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The window is a mismeasure.

It looks like the windows sit behind the outer skin of brickwork not in between - in which case ideally the window should have been wider than the brickwork and in inner plasterwork removed to fit.

it’s possible the new window was measured small enough to be fitted through the external brick opening, but the original was fitted from inside and plastered after. If that’s the case, you should have the options explained to you at time of survey: I used to do just that, ie: “would you like the new windows to fit behind the brickwork and there will an extra coat to replaster”

personally I think the result won’t look right in a period house, there will be too much frame visible, so won’t match the sight line of the originals
I think with the check reveals they tried to be clever and measure the window so it could be shuffled in one side all the way and then shuffled back the other till its central, I also suspect there's some frame extenders lying around somewhere that they couldn't get in because they'd lose the shuffle hence the daylight gaps, a combination of a surveyor trying to be clever and fitters who aren't clever enough

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