Acceptable Internorm window gap?

[alexo]

I'm currently having some Internorm replacement windows fitted.  All was going well when I saw them being fitted with compriband round the sides.  However, once they were in I was concerned by the 4cm gap at the bottom between the frame and the blockwork below. The window is sat on quite a hefty plastic rail, and in the pics you can see the gaps in the corners to the outside.  The exterior sills are yet to be fitted so I am hoping this might close some of the external corner gaps.

 

The window fitters are planning to fill these internal gaps with expanding foam and then add a plastic trim at the bottom to conceal this.  All three of our dormer windows have been fitted like this, with gaps ranging between 2-4cm. 

 

For context these are replacement for old dormer timber windows, and the surveyor who did the measurements mentioned there are often problems sizing for existing dormers.  The window fitters have assured me this is normal for replacement windows and they've fitted many Internorm installations like this without issue.

 

To me it seems pointless to pay for expensive passivhaus standard triple glazed units like this and push for compriband, only to have foam used in a large gap at the bottom.  I've requested the fitters to try to use a piece of wide compriband at the bottom in addition to the foam that will go behind the trim.

 

Is this gap acceptable and normal for a retrofit of Internorm or any windows for that matter?  Thanks

Edited April 9 by alexo
Attachments

[Alan Ambrose]

It looks like a mis-measurement or mis-manufacture to me.

[alexo]

So you think this is an unacceptable gap?
 

I don’t know what the max permissible or expected gap should be.  

 

On labcwarranty it says the maximum gap permitted for openings less than 3m is 10mm (per side). So 2cm would be fine if the gap is only at the bottom here.  Whereas I have a 3.5-4cm gap.  But I think this is guidance for new builds and new openings. I’m not sure if this is realistic for a retrofit?

[nod]

It is what it is But filling with foam isn’t the answer Tell them you want all gaps filling with silicone 

whilst foam is cheaper and quick it’s rubish for airtightness 

[MikeSharp01]

49 minutes ago, nod said:

Tell them you want all gaps filling with silicone 

whilst foam is cheaper and quick it’s rubish for airtightness 

If they use the right foam it is OK as it stays flexible and is designed for airtightness. E.g Illbruck FM330 Air Tight Expanding Foam.

 

How are the windows held in? Through the frames or with straps as this makes a difference to the air tightness detail.

 

[SimonD]

Just now, MikeSharp01 said:

If they use the right foam it is OK as it stays flexible and is designed for airtightness. E.g Illbruck FM330 Air Tight Expanding Foam.

 

How are the windows held in? Through the frames or with straps as this makes a difference to the air tightness detail.

 

 

I use the Soudal SWS stuff specifically designed for windows & doors - https://www.soudal.co.uk/pro/products/expanding-foam/1k-pu-foams/soudafoam-gun-win-door-sws#v11114

 

But 4cm does seem like a pretty excessive gap - what is the gap at the top?

[MikeSharp01]

Looking at the pics again I can see that they either forgot to add the packer at the bottom or were expecting that the wall would be higher beneath them as they open inwards they had to clear the sill.

 

[alexo]

29 minutes ago, MikeSharp01 said:

If they use the right foam it is OK as it stays flexible and is designed for airtightness. E.g Illbruck FM330 Air Tight Expanding Foam.

 

How are the windows held in? Through the frames or with straps as this makes a difference to the air tightness detail.

 

I’m not sure. I saw them drilling the frame in earlier for one. However another one has a strap poking through the exterior frame which was spotted late in the day and they said they would remove. This might be a fitting strap. They said this was a carry strap though. Will get a pic before they come tomorrow to show you what I mean.

 

Are different types of foam required for frames or straps? Thanks 

[alexo]

27 minutes ago, SimonD said:

 

I use the Soudal SWS stuff specifically designed for windows & doors - https://www.soudal.co.uk/pro/products/expanding-foam/1k-pu-foams/soudafoam-gun-win-door-sws#v11114

 

But 4cm does seem like a pretty excessive gap - what is the gap at the top?

I’m rather optimistically hoping there is no gap at the top. By the time I’d seen it they’d already sealed the rest of the frame so I don’t know.  I assumed they’d pushed it up as far as possible to leave such a large gap.

[nod]

40 minutes ago, MikeSharp01 said:

If they use the right foam it is OK as it stays flexible and is designed for airtightness. E.g Illbruck FM330 Air Tight Expanding Foam.

 

How are the windows held in? Through the frames or with straps as this makes a difference to the air tightness detail.

 

Big IF Looking at the care they have taken so far Do you really think they will use airtight foam Or just use the cheap shit that  they have in the back of the van 😂 

[alexo]

16 minutes ago, nod said:

Big IF Looking at the care they have taken so far Do you really think they will use airtight foam Or just use the cheap shit that  they have in the back of the van 😂 

😆 good point. I’ll double check it’s airtight.

[nod]

4 minutes ago, alexo said:

😆 good point. I’ll double check it’s airtight.

😁

[craig]

Absolutely not, they’ve f***ed up - it happens, we all do it and we all do our best to prevent it but that’s what’s happened based on the picture. You can see daylight bottom right.

 

Either the surveyor has f***ed up or it has been the estimator/order processor.

 

They have forgotten to add the 30mm transport strip that your internal cill butts up to and external cill connects to.

 

I’d like to see more internal and external pictures to give a definitive answer. However, on first glance they’ve f***ed up and I’d be expecting this to be addressed.

Edited April 9 by craig

[alexo]

8 hours ago, craig said:

Absolutely not, they’ve f***ed up - it happens, we all do it and we all do our best to prevent it but that’s what’s happened based on the picture. You can see daylight bottom right.

 

Either the surveyor has f***ed up or it has been the estimator/order processor.

 

They have forgotten to add the 30mm transport strip that your internal cill butts up to and external cill connects to.

 

I’d like to see more internal and external pictures to give a definitive answer. However, on first glance they’ve f***ed up and I’d be expecting this to be addressed.

 

This is the outside.  They said they couldn't do the cills since they didn't have a part so cills not attached.  I did think this was odd though since the cills are here on site.  The fitter plans to put sand and cement mortar over the foam gaps I believe.

 

I'll try to upload more pics of the inside before it was foamed.  Essentially the window was sitting on a plastic rail approx 4cm high that I could see internally before they foamed it.

[alexo]

8 hours ago, craig said:

Absolutely not, they’ve f***ed up - it happens, we all do it and we all do our best to prevent it but that’s what’s happened based on the picture. You can see daylight bottom right.

 

Either the surveyor has f***ed up or it has been the estimator/order processor.

 

They have forgotten to add the 30mm transport strip that your internal cill butts up to and external cill connects to.

 

I’d like to see more internal and external pictures to give a definitive answer. However, on first glance they’ve f***ed up and I’d be expecting this to be addressed.

 Another of the inside from before they added foam.  There were gaps visible to the outside on each bottom corner.

 

How would this usually be addressed?   I'm concerned because we've had 3 fitted already, all have bottom gaps ranging from 2-4cm.  The fitters say they're all going to be like this, and are returning today.  Should I get them to hold off and be insisting they replace the lot or is this overkill?  Or would getting them to redo it with an airtight foam and then negotiating a discount be more like it?  Thanks for the help.

[craig]

Do they have a plastic rail that sits recessed back from the front face of the window and recessed from the inside?

 

It should be about 30mm high.

Edited April 10 by craig

[alexo]

8 hours ago, craig said:

Absolutely not, they’ve f***ed up - it happens, we all do it and we all do our best to prevent it but that’s what’s happened based on the picture. You can see daylight bottom right.

 

Either the surveyor has f***ed up or it has been the estimator/order processor.

 

They have forgotten to add the 30mm transport strip that your internal cill butts up to and external cill connects to.

 

I’d like to see more internal and external pictures to give a definitive answer. However, on first glance they’ve f***ed up and I’d be expecting this to be addressed.

Another photo of the outside attached.

[RichardL]

Theres a ledge/cill to go in the outside surely although the window would sit on that normally - have they measured for a cill and not fitting it?

[craig]

This appears to be the recessed section, we call transport bead.

 

[alexo]

8 hours ago, craig said:

Absolutely not, they’ve f***ed up - it happens, we all do it and we all do our best to prevent it but that’s what’s happened based on the picture. You can see daylight bottom right.

 

Either the surveyor has f***ed up or it has been the estimator/order processor.

 

They have forgotten to add the 30mm transport strip that your internal cill butts up to and external cill connects to.

 

I’d like to see more internal and external pictures to give a definitive answer. However, on first glance they’ve f***ed up and I’d be expecting this to be addressed.

Separate window, separate problem.  The have left a carry strap wedged between the compriband and the wall on the right hand side.  This is showing from the outside, see pics.  What can they do to correct this?  Is it just a case of cutting it off outside or would they need to remove the entire window to get it out?  I'm concerned about it getting damp and impacting thermals. Thanks

[craig]

You external cills will connect to this but on the other picture, the compriband (black band bottom) is far too high and really shouldn’t be visible, even at this stage of the install.

[craig]

1 minute ago, alexo said:

Separate window, separate problem.  The have left a carry strap wedged between the compriband and the wall on the right hand side.  This is showing from the outside, see pics.  What can they do to correct this?  Is it just a case of cutting it off outside or would they need to remove the entire window to get it out?  I'm concerned about it getting damp and impacting thermals. Thanks

They’ll cut it off, nothing to worry about.

[alexo]

Just now, craig said:

They’ll cut it off, nothing to worry about.

Great, cheers.

[alexo]

4 minutes ago, craig said:

You external cills will connect to this but on the other picture, the compriband (black band bottom) is far too high and really shouldn’t be visible, even at this stage of the install.

So in summary, the window is too short owing to an error in ordering or measuring, and the compriband hasn't been correctly installed by the fitters?  Do you think these are severe issues, what would be a reasonable resolution in a case like this do you think?  Do I need entirely new windows or do you think that would be an unreasonable expectation.  If they use airtight foam to plug the gaps would this be good enough?  Thanks

[MikeSharp01]

They cannot sort the bottom gap because of the inward opening window. The problem there is the lack of sill packer - they should not have solved that with expanding foam if not a sill packer, but rather with and insulating block such as sold by Green Building Store then render over and make good. Overall the install looks awfull and the compriband should go all around and match the system requirements from Internorm which will specify depth, recess etc then the Illbruke foam goes behind that from the back. If you paid with your credit card I would put them on notice seek immediate replace / refit from the supplier.