Internorm KS430 sliding door seals question

[Mr Blobby]

I'm in the process of compiling a long list of issues for my internorm installers.  Widnows are fine, but the fitters were appalling.

 

I can't decide if the internal seals between glazing and frame on the slider is going to make the list and require some help please.

 

The sliding door seals are fine.  Very neat, very tight, very uniform.  In sharp contrast the seals on the fixed section look, well, rubbish.  The fixed section seals are a much softer rubber, all bumpy and judging by the condensation, not thermally terrific.

 

Here is the seal I mean, sorry about the picture, but it is very hard to capture the problem in a photo:

 

 

I am concerned that the seal may have been substituted, it is a bit crap compared to the other seals. 

 

Can someone with an internorm KS430 please put me out of my misery. Please check your door and tell me, are the internal glazing seals on the sliding section completely different to the seals on the fixed section?

 

Thanks....

Edited January 5 by Mr Blobby

[Nickfromwales]

Did they glaze these on site?

[craig]

Without seeing in person, it sounds like they may be been stretched slightly and then shrunk causing the issue you see in picture.

 

Is it the root cause of condensation? Hard to say as @Nickfromwales said, were these built on site? 

[Nestor]

We have HS330, triple glazed timber / aluminium lift sliding door.

A lot of timber in the doors and no condensation except outside on certain days.

No problem with the fixed seals.

Not an expert but would say fitting error.

Like you the fitters and some parts of manufacturers were poor quality. Disappointing.

Add to the list.

 

[mike2016]

KS430 lift and slide here - the fixed section seals pictured below:

My seal seems thinner to yours but is smoother. 

Sliding section seals are identical:

[Mr Blobby]

On 05/01/2026 at 22:42, Nickfromwales said:

Did they glaze these on site?

 

Yes, I think the fixed section only hence the isssue.  

 

On 05/01/2026 at 23:45, craig said:

Without seeing in person, it sounds like they may be been stretched slightly and then shrunk causing the issue you see in picture.

 

Is it the root cause of condensation? Hard to say as @Nickfromwales said, were these built on site? 

 

Currently being plasterd so humidity is in the 90s hence the condensation, but there is more on the fixed pane that was glazed on site.  For reference, all five of the other windows that were glazed on site have broken or porrly fitted trims with air coming through the holes in the trims on at least three of the windows.  So glazing on site was rubbish.  The fitters also left behind as box of internorm fix-o-round sealant that internorm supply to be applied round the glazing units.  The missing sealant is probably why the air is coming trough the broken trims, around the glaxzing units.  I did ask the fitters about the sealant at the time and they poo-poowd me, saying it isnt necessary.  That isnt what internorm would say though, so they will be refitting all the glazing with the sealant applied.  Although the box I have on site is out of date now.

 

 

On 06/01/2026 at 14:01, mike2016 said:

KS430 lift and slide here - the fixed section seals pictured below:

My seal seems thinner to yours but is smoother. 

Sliding section seals are identical:

 

Thank you for this.  So, your seals are the same on both fixed and slider section? That is very useful information.

 

I'm compiling my list today.   

Edited January 9 by Mr Blobby

[Nickfromwales]

11 hours ago, Mr Blobby said:

I'm compiling my list today.   

Go get 'em, tiger!!!!!!!

[JackofAll]

On 05/01/2026 at 22:19, Mr Blobby said:

I'm in the process of compiling a long list of issues for my internorm installers.  Widnows are fine, but the fitters were appalling.

 

I can't decide if the internal seals between glazing and frame on the slider is going to make the list and require some help please.

 

The sliding door seals are fine.  Very neat, very tight, very uniform.  In sharp contrast the seals on the fixed section look, well, rubbish.  The fixed section seals are a much softer rubber, all bumpy and judging by the condensation, not thermally terrific.

 

Here is the seal I mean, sorry about the picture, but it is very hard to capture the problem in a photo:

 

 

I am concerned that the seal may have been substituted, it is a bit crap compared to the other seals. 

 

Can someone with an internorm KS430 please put me out of my misery. Please check your door and tell me, are the internal glazing seals on the sliding section completely different to the seals on the fixed section?

 

Thanks....

The seals on ours are the same any thankfully  no waviness either.

[Mr Blobby]

18 minutes ago, JackofAll said:

The seals on ours are the same any thankfully  no waviness either.

 

I met with the fitter yesterday and he dismissed my concerns about the gasket on the fixed pane.  The slider gaskets are all concave and very neat and uniform, while the fixed pane is convex and horrible looking.  Fitter told me its a different gasket on the fixed pane so I think I'll ask internorm directly.

 

[Redbeard]

Who is providing the guarantee? Internorm (the 'kit' supplier) or the fitters? If, as I hope, the former, then they should inspect and sort.

[craig]

3 hours ago, Mr Blobby said:

Fitter told me its a different gasket on the fixed pane

 

It is a different gasket that is correct, it's whether it has been added correctly. We're only seeing a certain section and not seeing it in person but it does "appear" to be stretched. Usually when a gasket has been stretched, it causes the "ripples" you see. It's very unlikely to be the route cause of condensation.

[Mr Blobby]

47 minutes ago, craig said:

 

It is a different gasket that is correct, it's whether it has been added correctly. We're only seeing a certain section and not seeing it in person but it does "appear" to be stretched. Usually when a gasket has been stretched, it causes the "ripples" you see. It's very unlikely to be the route cause of condensation.

 

Indeed, the condensation at that end (condensation only appears when the humidity is in the 90s because of plasterers, while close to zero outside) of the window could be for any number of other reasons.

The gasket is a bit depressed below the glass for a few mm but I don;t think the fitters are going to remove the massive glass pane just to rectify a stretched gasket. 

 

Although it would be better if it was not all stretched and bumpy, and it will probably annoy me forever, refitting a big bit of glass for a small bit of aesthetic is probably asking a bit too much.  But it would have been nice if they didnt stretch the gasket.