70mm Cavity between window and brick. Is this OK?

Temas99 · 6 Mar 2017

Hi. My wife and I are currently having UPVC sash windows fitted across the whole first floor.

Having got four windows in place the installers have gone away to get architrave to cover the gaps, which are between 60mm and 80mm all around.

These seem like extremely large gaps to be filling and I wanted to know if this is common and if so how should we be expecting them to insulate that cavity.

Thanks for any advice.

motorbiking · 6 Mar 2017

it looks like they didn't measure the windows correctly. i'd be more worried about the length of frame fixers used and lack of solid packing material.

who was responsible for measuring the windows?

I wouldn't accept that in your shoes

TheVictorian · 6 Mar 2017

Perfectly normal for that scenario I would say. A photo from the outside would help but the old windows would have been sunk in half a brick's depth on the inside. That won't work with the new frames as they are thinner.

I have filled the gap on the inside of mine between the window and the brick with timber before fixing the new window to that, but foaming them in is also acceptable I believe.

motorbiking · 6 Mar 2017

there does seem to be only a single frame fixer in use each side. but agree that an external picture would help.

Temas99 · 6 Mar 2017

Thanks for the feedback. Mixed responses.

The guys doing the installation did the measurements. But I remember for this room they were unable to open the original windows because they had been painted shut, so there was some guesswork taken into account.

When we moved here the ground floor had already been done and from the outside I can that the amount of visible frame on the ground floor windows is about 5-15mm, whereas the amount of visible frame on the new upstairs windows looks about 40-50mm.

Here are some photos from outside.

Thanks again for your advice. Any more feedback very welcome before they return tomorrow morning would be good.

Temas99 · 6 Mar 2017

Regarding fixings. They have put screws directly through the frames into the brickwork. 2 at the top and I think just one to each side for each window. So 4 in total per window.

TheVictorian · 6 Mar 2017

Unless you specified that you wanted minimal frame showing I dont think they have done anything wrong personally.

Diver Fred · 6 Mar 2017

Umm, yes, well...

I wouldn't be happy with those windows and the way they are fitted. The amount of squity foam on the outside says to me that the guy doing the measuring up had no idea of the way the previous wiondows were made or fitted.
I guess the previous window frames were wood. The sash weight boxes would have been in the inside reveal* which is hidden on the outside by the brickwork. From your internal photo's I'd say you can see the some of the woodwork that made up the weight boxs has been cut away at the top of the windows. I guess the guy who did the measuring up probably measured up on the outside.
* in this case the space between the frame and the inner brickwork.

Probably difficult to request more fixings per window but you could try. What is much more important is to find out how they will be covering up the exposed foam on the outside - it needs cleaning up and the edges need properly sealing to your satifaction. I'd say you will have drafts and leaks around those windows negating the benifits of the double glazing. The fix needs to be on the outside otherwise you will be be getting damp into the walls.

Good Luck.

Temas99 · 6 Mar 2017

Thanks again. I understand there would always have been a sizeable cavity, but I also think their measurements are way out.

I did actually make a point to the sales rep at the time about not wanting too much frame showing. But at this stage I'm much more concerned about drafts and how that cavity is going to be properly insulted, made airtight and rain tight. He said that on the outside he will be using a strip of UPVC sealed against the window frame and brickwork with mastic. On the inside there will be architrave (although he will need to source 90mm architrave from somewhere).

I just stuck my head out the window with a tape measure and from my calculations at some points the space between the brickwork on either side of the window is just 10mm less than the width of the new window panel itself, so there is 45mm of the 50mm frame showing.

Should the whole cavity be foamed? Would it be better to get some Rockwool type insulation?

crank39 · 6 Mar 2017

OK let me start by putting right some of the doom merchants above.....

1/ Foam is better than leaving a void, more foam in the void or rock wool, your choice
2/ The windows couldn't of been measured much wider looking at it from the outside
3/ The windows have actually been fitted BEHIND the brickwork
4/ The foam squirting out is fine, that can be trimmed off and a quadrant bead or 30mm fillet stuck over the top, the bricks are all over the shop, foam and trim was the only way

Looks fine to me

vinn · 6 Mar 2017

The frames are wrong: they were wrongly measured up, and wrongly installed - they look like a DIY amateurish effort.
The architraves were not cut paint-loose before removing them, & plaster has been spalled : probably because whoever didn't know how to remove D/H box frames - always amateurish signs in my book.

The frames will have to come out, and there either be a rethink or a replacement - as things stand you will have water penetration (as noted above) at the reveals, and wind whistling through the gaps.
The two fixings (per frame?) have already been pushed back so the frames are now insecure.
I wonder whats happening down at bottom rail/cill level?

All this plastic for what were possibly wonderful wood original frames - frames that could have been renewed to modern standards in-situ or on the bench for a fraction of the price of Pvc replacements.

Temas99 · 6 Mar 2017

crank39 said:
3/ The windows have actually been fitted BEHIND the brickwork

Thanks for your feedback.

Just to pick up on your point 3. I specified to the sales rep that I wanted about the same amount of frame hidden behind the brickwork as on the ground floor (which had already been done many years ago) and basically as little as possible showing, so that they looked as authentic as possible. If this had actually been done, the new window panels would have been at least 70mm bigger than they are (35mm on each side). As it happens in some places there is less than 5mm hidden behind the brickwork. That is pretty slack.

crank39 · 6 Mar 2017

I'm not privy to what was discussed between you and the salesman but I would imagine a surveyor attended some after the salesman to take a more detailed survey, maybe your concerns would of been better aimed at him rather than someone who is just after a signature, the upstairs as a stand alone install to me looks perfectly fine, if your now saying they don't match the downstairs then I'll bow out from here as I can't add anymore

DHFrames · 7 Mar 2017

Looks like they've brought the frames in slightly to finish flush with the plasterline, hence the gaps outside. Easier to finish off inside that way
Every installer does it different, I hate the sight of plastic round a sash window, personally I think it defeats the object of paying the extra for traditional looking window then chucking plastic round.
All the best if you need to call on Synseal to deal with any issues within the Guarantee, their aftesales is shocking, used them for 7 yrs, the manufacturing quality has rapidly gone down hill this last year

motorbiking · 7 Mar 2017

I'm assuming they are registered competent persons from a building control sign off point of view or is this something you are meant to do?

It doesn't matter who you reported your requirements to, they've formed part of your contract giving you the option should you choose, to reject the work.

In your shoes I'd reject it. The fact they are having to find some non-standard finishing materials should be enough to make you think they got it wrong.

The question I'd put to those saying it is all fine, is this: Would it be better if the windows were another 2-5cm bigger each side?

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70mm Cavity between window and brick. Is this OK?

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