UPVC Double Vs Secondary Glazing

So I currently live in a townhouse super close to a 4 lane main road, which can get pretty busy during rush hour. Our master bedroom is on a third level facing the road which we are about 4 meters away. The master bedroom is also made of weatherboard, so I know that it effects sound leakage as well.

Thinking what would be the best for doing up our windows for maximum noise reduction, as we can hear every car that passes by. From what i've been told, our windows are currently double glazed, but they are still not as effective. Would uPVC be that much better or you recommend secondary glazing?


  • +2

    A busy 4 lane road 4 metres away.

    The only way to stop the noise is to move.

    Source: science (acoustics)

    • That's not really an option right now. Just got into a 4 year mortgage… didn't think the road noise would be that bed from the bedroom until bought.

      • Is their noise insulation between the weatherboards and plaster?

        • No idea. I thought the windows and balcony door would have been the main source of leakage to focus on, before looking into this?

          • @crimsondarkn: As you stated weatherboards are very poor sound insulators. If you are on the top floor you may be able to fill wall voids with sound insulation via the roof space.

      • Make more of your own noise… other noise wont be an issue.

  • +2

    What do you mean you have been told your windows are double glazed. Have a look at them you should be able to see the two panes of glass and a vacuum gap between them. My house in the UK had uPVC double glazing and it did a good job of noise reduction. It doesnt block it all but it helps. How long have you lived these also? If its a new place you might find you get used to the noise in time and hardly notice after a short time.

    • They are double glazed, but it's not uPVC, so with my current issues, I would imagine the double glazing is not that strong. I got a couple of quotes from window companies who said they were indeed double glazed windows. I've been living here for about 1 month so far. I don't think the noise will get better, because I would imagine more people on the road during summer.

      • +1

        I would hold off a little longer before taking any action. I moved into an apartment near a main road and a railway, I remember in the first few weeks plotting all kind of things to try and plug up the bedroom windows but after a while (don't remember how long) I honestly didn't notice it anymore…

        • It's more the bikers roaring in their motorcycles, the trucks/buses, and the cars speeding above the road limit that bugs me. I sleep with earplugs every night and tried blocking out the balcony door with foam mats.

  • I don't need the place to be brand spanking quiet, I just need it to be enough to block out the majority of normal car noise.

  • +3

    Won't matter what you do to the windows if the hl noise is just gonna come through the walls.

  • +1

    our windows are currently double glazed, but they are still not as effective. Would uPVC be that much better or you recommend secondary glazing?

    If your current windows are double glazed, then secondary glazing will help the most, uPVC are good, but most are double glazed so not a huge increase in sound blocking.

    Also you might need to look at the wall insulation and if there is anything you can do outside to direct the sound 'away' from the house to start with.

  • Acoustic engineer here. Unfortunately in your case it sounds like the noise is most likely coming through the weatherboards and any other penetrations (openings) you may have as double glazing is typically the first point of treatment for houses.
    It may also be worth checking if your state has a noise abatement program for road traffic noise and read up on eligibility, for example NSW has this: https://roads-waterways.transport.nsw.gov.au/about/environme....

    • I feel like alot of the noise is coming through my balcony door.. which was why I'm thinking to secondary glaze it with another door. Getting an acoustic wall specialist to see if weatherboard is the main issue. The secondary glaze folks say they can probably cut the noise by 20 to 30 pct with secondary glaze. Unfortunately I can't block the road…

      • Yeah a door changes the situation completely, especially if the door either doesn't have seals or doesn't seal properly. Rule of thumb is that the acoustic performance of a wall or partition is that it is only as good as the weakest point.

        • Well it's a single glass door which opens. I can tell there's some leakage for sure. Would you secondary glaze or upvc double glaze? Or just block the door with some wood? lol

          • @crimsondarkn: Doors and openable windows are often the weakest point due to its reliance on seals. You need to make sure you have good seals on all four sides. You could secondary glaze with an additional door (so you have one door opening in, one opening out) which would be quite effective if done right, especially if you can seal both doors, or maybe consider changing to a heavy solid door or a changing your glazed door to 10 or 12mm glass.

            Is your balcony balustrade open? You could look to make it solid to the floor which may have a small effect.

            • @frostface: Also I’ve heard that uPVC isn’t suited to Australian heat as its predominantly a European product, although it might be getting better.

              • @frostface: Yeah, i've been told upvc was good for noise reduction? But it seems like you folks are implying that secondary glazing will be better overall for noise reduction, and more cost effective. Given that the windows are already currently double glazed (but shotty work), so replacing with upvc double glazing wont make a huge difference? Correct me if i'm wrong

                • @crimsondarkn: I think uPVC has a good reputation because they seal really well, plus double glazing seems to be standard, so they would probably have some of the highest Rw numbers. So I think it will be better than what you’ve currently got, however, acoustic engineers love glass that you can achieve a 100mm air gap in between, which effectively what secondary glazing system will look to achieve.

                  Keep in mind what philme said, sound makes it way to the weakest point, i.e your door. Even if you upgrade your windows your door is always going to be your weakest point. Fix your door first and then see if it makes any difference.

                  • @frostface: Yeah, I was gonna fix the door first and see what the outcome would be. However, I have the option to replace the door with either a new upvc double glazing door, or a secondary glazing door ontop of the existing double glazed door. So that's my current dilema…

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