Acoustic glazing / sound proofing issues

3 Mar 2021
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United Kingdom

I’ve recently had new windows fitted, PVCu casement windows, acoustic double glazed and argon gas filled, with the intention of reducing traffic noise. The property is Victorian and right and on a busy road. Just a pavement width away from the road. The new windows were fitting into the old sash frame. There has been zero reduction in sound.

I’ve had the company come back to see if they can do anything. They have suggested filling the old sash frame with foam. I’m not hopeful this will work.

Would really appreciate some advice on this. Is the foam insulation worth trying or am I wasting more money?
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What type of windows were installed prior to the upvc ones and were they single or double glazed? If you've gone from single to double glazing there should be at least some reduction in noise levels. However, given you're only a pavement width from a busy road, I expect you'll always need to accept a degree of traffic noise.

And what do they mean by fill the old frame? I'm assuming they mean fill voids that have been left between the old frame and the brickwork of the house?

A few pics of the install, especially where the new frames meet the old and any gaps would be useful :)
Thank you for the replies so far.

I had UVPC double glazing before. They were about 10/15 years old.

I’ve attached a photo of the new windows and how they fit against the old sash frame. They have suggested filling this frame with insulating foam. It’s only now, after installation, that this is being discussed, I feel like this should have been mentioned during quotation stage. Especially as they knew the only reason I was replacing the windows was to reduce noise. I may have made a different decision regarding the old sash frames.

I’ve started to looking into secondary glazing, but not sure if trying the foam first will help at all.


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Do you have cavity walls or solid? If solid, wall vibration due to traffic may be a main source of the noise entering the house.
This is only my opinion. When it comes to trying the option of foam filling any cavities in the original framing, I wouldn't be trying this (for now) based on the pic you've posted. You'd either have to take the architrave off or drill exploratory holes to see what kind of cavity exists. It would be a shame to disturb that original woodwork unless absolutely required.

If it was me in the situation you're now in, I'd try the secondary glazing on one window to see if it helps. Perhaps you could try a diy option such as these if you're confident enough?

DIY Secondary Glazing Kits | Clearview Secondary Glazing (
Magnetic Secondary Glazing - Double Glazing Kit | The Plastic People

If you then find the secondary glazing helps, you can consider if you want to have the remaining windows done, either by you (essentially more of the diy approach) or by a professional company. If you find the secondary glazing makes no difference, you might be faced with considering trying the cavity foam fill on one window, again to see if it makes any difference.

Hope this helps at least a bit and good luck :)
Thank you, this is really helpful. It’s going to cost £100 for them to apply the foam on one window. I’m not confident it’s even going to help. Best to put that towards some kind of secondary glazing.
Secondary glazing usually works best acoustically, at 120mm away from the existing window.
Problem with noise from roads is you have to look at glass used..if they have not used either a standard laminate or better still acoustic laminate , the noise reduction will have been soo marginal. Also you need to take into account other places that noise can enter the property . Do the new windows have trickle vents? Have you an open fireplace , or even Woodburner? Both of these will let external.noise in, even poor loft insulation. I suspect windows alone , even with acoustic secondary glazing, you are still going to get a certain amount of noise and certain frequencies more than others
One question I have, is what is inside the sash weight boxes? In most vertical sliding sash windows there are two of these (one either side) and they are a conduit of sound transmission as are any gaps between the window frame and the masonry. Packing voids with mineral wool (Rockwool, etc) can often reduce sound transmission
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Exactly what I was thinking, the boxes are hollow and I'd bet they still have the weights inside, it really is a cheap way of doing things - fitting a decent pvc window into the existing box, ok you don't have the mess, the dust, the plastering and maybe the customer didn't have the budget but fitting them this it fraught with problems, at the very least I'd be filling up those boxes

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