Double Glazing

[barry1010]

Sitting in my peaceful lounge with doors and windows closed. Should I really be able to hear the birds singing outside? Not raucous kawing of crows, gentle tweets and cheeps.
Is this a sign my windows are shot?

[The Builder]

The window and door seals actually do more for sound-proofing than the glazing.

uPVC?

[barry1010]

Yes

[barry1010]

I was remembering the old Everest adverts where it was blowing a hoolie outside or jets were flying overhead and there was total silence indoors

[The Builder]

Ted Moult? :o)

In that case, Barry, seals on uPVC are normally very good.
Perhaps just check that nothing's warped, and everything's closing properly.

DG does work well, but high frequencies are the hardest to block.
I don't want to show off, but with my triple glazing, WW3 could be going on and I'd never know ;o)

[barry1010]

Show off :D

I've checked all round and everything closes tightly and I haven't felt any draughts. No misting or fogging between the panes.

As long as it is keeping the heat in during the winter and the draughts out, that's what matters.

Is there any way to measure the efficiency of the double glazing and windows? I don't have a clue

[The Builder]

I built a function room once for a pub in the middle of a village.
For the sake of the neighbours, we had heavy (6mm plate glass) secondary over normal double glazing.
To test it, I put The Chemical Brothers on the juke-box, cranked it up, and went outside and had a listen. It was pretty good too.

Anyway, the scientific way I guess is to use decibel meters maybe?
In your case, being draught free is probably the best indication that everything's as good as it's going to get.
As I said: birdsong is very high frequency.

[barry1010]

Thank you, once again. It is a rare treat for me to sit in this room in silence, the windows are probably exactly as they were when they were fitted but it's never been quiet enough for me to hear external noises

[Buenchico]

While this page, from Everest, is obviously designed to get people to buy the company's products, it's actually also rather good at explaining about all of the routes that sound can follow to get inside your home:
https://www.everest.co.uk/windows/noise-reduction-window/

[The Builder]

That's a really interesting read, Chris.

[barry1010]

Very interesting, Buen, but they recommend covering up air bricks. Surely that is a big no no

[barry1010]

Builder, it also says double glazing is better than triple for minimising sound.

[Buenchico]

The professional solution to allowing air to flow in and out but keeping sound to one side or the other:
https://www.soundservice.co.uk/acoustic_vents.html

[The Builder]

Haha. They would say that wouldn't they?

What they don't say, is that it's the glass thickness that makes the difference. (Which is why I mentioned 6mm plate above.

In small windows, they may use 3mm glass for triple G.
The larger the window,, generally, the thicker the glass needed.
Good glazing uses 4mm normally. For a huge window, I once had DG units made of 10mm glass.

What they're not doing is comparing like with like.
Sound waves work by compressing the air. Thin glass will vibrate more than thick.
So, given the same thickness of glass (4mm) three panes are always going to be better than two.

Then there's the 'cavity spacer' (distance between the panes of glass).
That affects things as well.
Chris's article has a good load of sense in it, but It's still just 'marketing.'

[The Builder]

There shouldn't be any need for air bricks in a room unless there's a woodburner or open fire (even then, there are better draught-free ways of doing it.)

I guess they mean airbricks for suspended timber floors. They should never be obscured.

PS... maybe your 'trickle vents' are open?

[bhg481]

The gap between the panes is the key to soundproofing; unfortunately you need a smaller gap for heat insulation than you do for sound insulation. When I first started work I worked on an airfield, a government test establishment. The windows were the old single-glazed metal type but they had installed a second set on the inside of the window ie, a 9 inch gap between inner and outer windows purely for soundproofing. With a V bomber running up on the apron immediately outside the office you could barely hear it so long as both sets of windows were closed. Open just a single window and the difference was amazing.

[barry1010]

I have no trickle vents. Not a one

[barry1010]

My house is built on a slope so there is quite a deep space under my living room floorboards, that's where the air bricks are, below the floorboards

[The Builder]

Good post from bhg.
Maybe others might may want to add their experiences.
Sounds like your fenestration is fine Barry :o)

Just enjoy the birdsong.

[The Builder]

Carpets?

[barry1010]

Lovely 100% wool carpet with lots of underlay