Laminated Window Glass: moisture ingress & u-value

[Possom]

I'm considering either option below for certain double-glazed windows and a door.


a) Outer pane 6mm thick and inner pane 4mm.

b) The use of Pilkington Optilam Phon laminated glass.
http://www.astrasealdownloads.com/files/optilamphon.pdf


Both options would reduce external noise and also increase security.

Would option 'a' reduce the u-value?

With regards to option 'b', I've heard that long-term laminated glass can get moisture ingress between the panes and can look "milky" white around the edges of the glass. Are there any comments about this, and could this phenomenon potentially affect a good brand such as this?

 

[ronniecabers]

Not too sure about the U value issue, but your costs would increase!

As goes for soundproofing, just bear in mind that you window will only be as good as the rest of the property...eg if you have an open fire you will here a lot of external noise, also something to consider , is what noise you are eliminating as certain glasses only reduce certain frequencies.

As a rule Laminate glass is easily affected by Linseed oil in putty and you would certainly see ' milking ' in a single glazed format put in with putty. In a double glazed unit, providing the unit is never in water then you should be absolutely fine. Anther little trick is to have a ' foil ' tape protecting the laminated pane, to stop any potential water ingress, but on the downside if water gets in , tape can well withhold the water closer to the glass.....

 

[Gazman16]

That link indicates decibel reductions of around 35-48.
If you google that your looking at little more than whispering or leaves rustling. That is in laboratory conditions too and the cost is extortionate.

Imo you better off just going for normal double glazed windows and one there in if you want more sound proofing you can get some nice heavy curtains or secondary glazing with the money you saved.