What do you think of this window section? Worth worrying about? 😬

[fatgus]

This is a cross section of our top (for several reasons) window contender… would you be worried that the highlighted bit doesn’t have a designed-in slope? It’s been suggested, by another supplier, that the flat rebate means that rain that gets past the seal (arrowed) would potentially sit on that flat area without draining, causing rot in the long term… that makes sense, but is it a real cause for concern?

 

I’ve compared with a few other manufacturers’ cross sections and most seem to be like this, with just a couple that have a slight fall on the rebate below the glazing unit….

 

Any thoughts gratefully received… I thought our window choice was almost made (just awaiting one more quote) but this question makes me nervous!

 

I shall now return to my much needed evening gin. Thank you all 

 

 

[Iceverge]

Those frames don't look hectic. 

 

What's the Uf value? 

[fatgus]

31 minutes ago, Iceverge said:

Those frames don't look hectic. 

 

What's the Uf value? 

Not sure, but the average Uw over 95sq.m is 0.88. …

[fatgus]

Sorry @Iceverge… not sure what you mean by “don’t look hectic”?

It seems as though the rebate on the fixed windows has a fall…

 

 

 

[BotusBuild]

My take on this. All the mullions have slope, whether fixed or opening windows which is good.

The bit you are questioning is glazing fixed into the frame. In essence, once fitted with the seals all in place correctly, the glazing should not move relative to the frame as designed. The possibility of rain getting into that area between the bottom of the glazing and the frame should be zero as long as they are manufactured correctly which we should assume they will be.

You're going to be checking all the seals in these units when they arrive,  like I did, aren't you (Hint!). Check for any where you suspect they have put the join between the two ends of a seal anywhere else except the top of the frame. We had 5! glazing units removed after fitting to have the seals replaced and fitted correctly. 

[fatgus]

16 minutes ago, BotusBuild said:

My take on this. All the mullions have slope, whether fixed or opening windows which is good.

The bit you are questioning is glazing fixed into the frame. In essence, once fitted with the seals all in place correctly, the glazing should not move relative to the frame as designed. The possibility of rain getting into that area between the bottom of the glazing and the frame should be zero as long as they are manufactured correctly which we should assume they will be.

Thanks @BotusBuild I’ve been through quite a number of drawings and can only find a few (e.g. Nordan & Rationel) where this element is sloped, so I figure it can’t be too much of an issue. Most of our windows are fixed anyway.

 

16 minutes ago, BotusBuild said:

You're going to be checking all the seals in these units when they arrive,  like I did, aren't you (Hint!). Check for any where you suspect they have put the join between the two ends of a seal anywhere else except the top of the frame. We had 5! glazing units removed after fitting to have the seals replaced and fitted correctly. 

Great tip 👍👍 To be frank, not something I’d considered… definitely added to the check list 😁
 

 

 

[fatgus]

Thinking about this a little more, I imagine that provided the dimension in red below is adequate, any water that defeats the seal above will drip onto the sloped part anyway… most unlikely to make its way onto the horizontal area. A non-issue, I suspect!

 

[craig]

No, no slope required as that is the area where the glass packers need to be.

 

It is externally glazed though, which means the cladding needs to be removed to get access to the glass if it breaks/fails. This is the case for most outward opening systems, the clips break when removed, so they need to be replaced and service engineers absolutely hate them, as it's it a lot of time (money)/effort to remove all the cladding, place the clips back, and fix the cladding back on. That also means they need to have the right tool to turn the clips to hold the cladding in place (they get broken removing the cladding, easier to snap the lug than turn the clip).

Edited 1 hour ago by craig

[craig]

3 hours ago, fatgus said:

, any water that defeats the seal above will drip onto the sloped part anyway

 

I would say that is the intended design.