Double Glazing for Noise Reduction

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Dingbatt

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#230599 4-Mar-2018 08:50

As a subdivision beyond our suburb has steadily filled in, the traffic on the road past our house has increased to the point where it intrudes on my well-being. It's not State Highway busy, but the increased traffic combined with A-holes who think everybody likes listening to their petrol powered wet dreams is driving me nuts.
We have ducted air-conditioning and so have been able to have the windows closed most of the summer.

I am now considering double glazing as the next step in our house improvements. As far as I can tell, double glazing is done for thermal insulation primarily, with secondary benefits of UV filtering and acoustic insulation.

In my case, I would like for the acoustic insulation to have a marked effect on the road noise. We have two large ranch sliders and a couple of picture windows that all face the road and are single glazed. The house is 1980s weatherboard with an iron roof (fully insulated with Batts). Am I hoping for too much to expect that double glazing will noticably reduce the transmission of noise into the house? Or will it just find another pathway? My internal walls are wooden sarking so it is not a simple option to add acoustic insulation to the walls.

The next step is to get an acoustic engineer out for a consultation.

Any comments from GZers who have retrofitted double glazing, on the acoustic benefits achieved would be appreciated.

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#1967744 4-Mar-2018 08:58

Our last house, character home, weatherboard, we fitted double glazed windows. Not retrofitted as in add another pane, but new windows all round. It made a marked difference to sound.

Where we are now, new home, we have the same road issue. Its now a popular way to get from Halswell to Hornby in ChCh. But we have no issue as the windows block a lot of noise. Next door might be mowing lawn, open window = noisy, close window = quiet.

Im not sure how it is with adding double glazed to a single glazed window as compared to a new double glazed unit. Or as I assume you are not wall insulated, how much that helps. Our old place we reclad and did the windows at the same time so walls were batted

RunningMan

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#1967767 4-Mar-2018 09:45

Double glazing will certainly help with noise transmission through the window, but you've also got to think of how else noise enters the building. Gaps in the weatherboards, transmission through from the ceiling space etc...

Dingbatt

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#1967768 4-Mar-2018 09:47

Thanks tdgeek. House is fully insulated with Batts and am looking at replacing the current aluminum single glazed joinery with double glazed units.

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elpenguino

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#1967779 4-Mar-2018 10:04

If you want noise attenuation you require different glazing units in the window.

The panes of glass are spaced further apart for noise than for thermal purposes.

Most of the posters in this thread are just like chimpanzees on MDMA, full of feelings of bonhomie, joy, and optimism. Fred99 8/4/21

Goosey

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#1967783 4-Mar-2018 10:18

Those 1980s batts wont be perfoming as well as they were.

IMHO, the glazing will help and given the age of the current frames and windows then will likley add value to the home.

Dingbatt

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#1967796 4-Mar-2018 10:22

elpenguino:
If you want noise attenuation you require different glazing units in the window.

The panes of glass are spaced further apart for noise than for thermal purposes.

Are these still Incorporated in the same element? Or do you mean discreet units separated by an air gap? I.e. the outside and inside of the window frame. Like Magnetite do?

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afe66

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#1967803 4-Mar-2018 10:52

We retrofitted (retained wooden frames) our 1920 villa with double glazing for warmth and found there was a noticeable reduction in road noise as a nice side effect.

Our house and bedroom is on a corner of a sloping street so we would hear (during the day when I was sleeping) a lot of hill starts. I cant say it really bothered me before but afterwards we all commented on how much quieter it was.

We still have the thermal backed curtains up from before the install too.

The windows in the bedroom were a set of bay windows as you get with villas so 8 panes and another a smaller window.

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timmmay

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#1967807 4-Mar-2018 11:01

My old house had wooden windows with inch thick wooden frames, they had a cheap retrofit double glazing which was 3mm thick plastic on the inside. When we replaced them with proper PVC double glazing a LOT more noise came in. Better heat insulation though.

I suspect there's not much noise transmission through the glass, but the glass panels sit on spacers so noise can go under the glass. There's only a couple of thin bits of PVC keeping the noise out. If they'd filled it with foam or something maybe it'd have been ok, but in our case it made things louder.

elpenguino

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#1967867 4-Mar-2018 12:43

Dingbatt:
elpenguino:

If you want noise attenuation you require different glazing units in the window.

The panes of glass are spaced further apart for noise than for thermal purposes.

Are these still Incorporated in the same element? Or do you mean discreet units separated by an air gap? I.e. the outside and inside of the window frame. Like Magnetite do?

Yes, still incorporated in the same glazing unit, just further apart and sometimes thicker glass or glass with slightly different properties.

If you were glazing for acoustic purposes you would need to understand that air carries sound so you must seal up your building penetrations well. This is all going to be for naught if you had a house with poor sealing elsewhere.

BTW discussion around glazing suffers confusion from incorrect use of the term double glazing to also cover secondary glazing.

Secondary glazing is the magnetite thing (etc.) with a layer of another glazing material which is not in the same frame as the first layer of glass.

Most of the posters in this thread are just like chimpanzees on MDMA, full of feelings of bonhomie, joy, and optimism. Fred99 8/4/21

jonathan18

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#1967880 4-Mar-2018 13:38

My brother lives on a main thoroughfare in Wellington in a 1900s villa; he had many of the windows retrofitted with double glazing and says there’s been a significant reduction in the noise coming from the street. He’s happy enough with the results that intends to get the last windows redone as well.

I don’t believe this was any different to the methods aimed at improving insulation, as I imagine there’s not much room to increase distances between panes in the old sash windows.

nickb800

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#1967881 4-Mar-2018 13:44

Nzta has a guide to dealing with road nose, albeit from highways. It says that double glazing has a pretty marginal effect, mechanical ventilation is more important (which you have). A glazing arrangement with 100mm between each pane is most effective, like what you get in fancy hotels like Langham Auckland.

Note large PDF
http://www.nzta.govt.nz/assets/resources/state-highway-guide-to-acoustic-treatment-of-buildings/NZTA-Acoustic-Treatment-Guide-v1.0.pdf

mattwnz

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#1967925 4-Mar-2018 15:27

Ask you glazier about hush glass too.

morrisk

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#1967934 4-Mar-2018 16:07

Another option I think worth looking at is increasing the thickness of the glass without going to the double glazing - is that what "hush glass" is?

Shoes2468

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#1967982 4-Mar-2018 19:23

morrisk:
Another option I think worth looking at is increasing the thickness of the glass without going to the double glazing - is that what "hush glass" is?

I think it would make a big difference we did this in our bedroom windows and it made a big difference. Double glazed with one pane of the glass being “hush” glass we never called it that, but basically it was safety glass, my understanding is one of the panes it was glass then some resin to dampen the noise then a second pane of glass all Moulded together. Then a second pane of ordinary glass

gabba

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#1967992 4-Mar-2018 20:17

We did a 50 year old house that sits above Sh2 motorway in Lower hutt. Emergency services use the area alot as do trucks and drivers that can afford expensive cars but then can't afford to put proper mufflers on!

It was retro fitting into wooden frames. We took out glass that was about 3mm and put in glazing units with combinations of 4.5mm and 6mm glass. Glazier also put up sealing strips around the opening windows.

Noise wise it made a big difference. We still hear the emergency services but it's more muffled and less annoying. We don't hear general traffic noise. Just the odd noisy car or bike in the background if we are quiet in the house. It made a big difference for us.

Find yourself a good glazier and make sure they know you want to reduce noise. They will size the glass unit for you accordingly.

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