Re: Secondary Double Glazing

[Owain]

"Barry Young" wrote | I'm thinking about geting secondary double glazing for the bedroom in my | flat as there's a fair amount of noise from the road just outside. A couple | of questions. | 1) I quite like the look of the Newdawn kit that DIY plastics are selling |

They sell it in 3 and 4 mm | thicknesses in both polystyrene and acrylic. The acrylic kits work out | about 25-30% more expensive than polystyrene - is this worth the extra? | From what I can gather they're a fair bit more durable and less likely to | get "cloudy".

Hmm, I would be inclined to go for glass as being heavier.

| 2) I've heard that the larger the gap between the two "windows" is, the | better the noise reduction. As the window reveal is about 35 cm deep, I | could make the gap this size, making the secondary glazing flush with the | walls - would this make sense? Or should I aim for a smaller gap?

The pub near me has got sealed double-glazed outer, single secondary glazing over that, and then another (I think double) glazed inner, with about a foot depth between the secondary glazing and the inner. This was to stop sound getting out, not in :-)

Making sure the outer (existing) window is sealed airtight and lining the reveal with accoustic tiles will also help.

Owain

[Nick Nelson]

2) I've heard that the larger the gap between the two "windows" is, the

> better the noise reduction. As the window reveal is about 35 cm deep, I > could make the gap this size, making the secondary glazing flush with the > walls - would this make sense? Or should I aim for a smaller gap?

Yes, good sound insulation needs a much bigger gap than is desirable for thermal insulation, but 35cm is probably much more than you would need.

About 4 inches (10cm) is almost certainly enough. Interestingly, you have the scope to make the secondary pane non parallel with the outer. This is the approach used in sound studios to reduce resonances between the panes and improves sound isolation even more.

If you can arrange it, and wouldn't mind the sloping appearance, making the gap at the bottom (say) 10 cm and the gap at the top (say) 15cm ought to be pretty effective.

Nick.

[info]