Traffic noise despite triple glazed windows - help

Hi pinsters
I recently purchased a house at the front of an estate that looks onto a secondary road. I spent a good deal of money upgrading the house i.e. installed triple glazed windows, insulated walls with 102cm kingspan, insulated attic upgraded plumbing and heating etc. I am delighted with the outcome but there is traffic noise entering the house which gets louder at night when of course the house is quiet. The speed of the cars at night is also increasing the noise. Given the instalation of 42cm triple glazed windows with 3 4mm glass panes I thought this would eliminate all the traffic noise but it doesnt. I also think noise may be entering through the airvents. Can anyone provide any solutions I am now thinking of replacing glass in windows with acoustic glass and changing the depth of the 3 panes but this is obviously very costly. My understanding was that with triple glazed windows you wouldnt even hear the birds outside but this certainly isnt the case. I know the windows were fitted correctly and foamed. Has anyone any ideas of a cheaper solution? Despite blocking the air vent temporarily in one bedroom the noise is still there. Any help and advice would be greatly appreciated.

You could try secondary glazing. Not the most attractive but meant to be effective for reducing noise.

Have you a front garden or are you right on the street? Could you plant trees, hedging, etc… to muffle the sound?

Thermal camera the front of the house to identify any gaps in the insulation.

Fill any gaps as appropriate, however road noise is extremely difficult to eliminate entirely.

Put up a speed camera sign up outside your house…

If you block up the vents does that make a big difference? Try it. Remove the cover and stuff in a towel or something. If that deals with the problem it might be worth considering up grading the ventilation system. It might make sense to consider a heat recovery ventilation system that does away with the vents, eliminates road noise, and saves a bit of money on the heating too.

Unblock the vents after the test because they are quite important.

Are you definitely sure it isn’t the air vents? There is some ways to block them discussed here:

I live in an apartment that faces a noisy street and it is really quiet, well, until you open the windows. As well as the usual double glazed windows it also has the heat recovery vent system. I would recommend double checking that it isn’t the air vents and if it is, then perhaps installing this.

Our house fronts on to a road which while not too disturbing was bothering me with noise. We had UPC double glazing.

After a lot of home work and becoming slightly compulsive obsessive we replaced the windows with single pane sash windows and had a better sound insulation effect.


Its a common misconception that double glazing is quieter than single pane. Double glazing is excellent for heat insulation but can be poor for sound. Most window installers don’t pay any attention to sound insulation when installing.

To have a good sound insulation result follow these steps.

  1. Use a solid frame (wood is excellent)
  2. Eliminate leaks between the frame and the wall. The entire frame must be tightly sealed with expanding foam. Any air gap will allow transmission of sound.
  3. The glass: see below

Every pain of glass will transmit sound. Each thickness of pain will be most efficient at a particular frequency. Laminated glass (two panes stuck together) stiffens both pains and the laminate gel also acts as a sound buffer. If the two pains are of different diameters the lager the difference will result in less sound transmission.

Examples of laminated glass can be found at airports, banks shop fronts etc.

In our windows we used 3mm pains of old style cylinder glass for the old sash effect laminated to a 6mm pain of modern float glass. The sound insulation from this single pain is excellent.

Double glazing will improve the effect with a wide gap ~20mm with 2 sheets of laminate (4 pains) all of different diameters this will give you the maximum sound insulation effect.

There is a company that also sucks out the air in between the pain creating a vacuum which means the only sound transmission is via the frame.

As a general rule the more mass to your window the better the sound insulation.

FWIW I think you have been miss sold triple glazing which is good for heat insulation but as I understand its sound insulation is no better than double glazing.

Secondary glazing will also work but is ugly.

Sounds like you breached the building regulations. New windows need to comply with building regs - which means that by now only high grade double glazing or triple glazing may be installed.
Except for protected structures.

It’s a protected structure, it was the previous owners who ripped out the old sashes to put in the UPC double glazing on a 200 yr old protected structure.

The planneres were obviously too busy granting all that planning permission in the the past to notice or care.

Hi Guys,

I find myself in a similar situation to the OP. I was think of installing secondary glazing in 3 really big windows that i have in the apartment, has anyone any experience of this?

I’ve got my doubts about what you are saying here in terms of breaching the building regulations. Specifically the part that you are stating in bold.

Could you please identifiy the specific building regulation that you believe is being breached in this instance? Like the actual building regulation e.g. L2, C3 etc. and even better what particular Technical Guidance Document Section that might give reference to same?

For an existing building I don’t believe that applies. And I’d be saying more so that just them so called “protected structures”. A like for like replacement, OR, better is generally satisfactory for building regulation purposes.

For what it’s worth the building regulations have actually becoming practically unachieveable aside from adopting German bulidling materials and methods given what we see in Part L 2011 Domestic (and I’m talking about new builds here).

Part L: This amendment applies to all works to existing dwellings that are covered by the
requirements of the Building Regulations, including extensions, material alterations, material changes of use and window and door replacement.

Thank you Superman. I have been educated.

How is the house furnished? These days a lot of people have uncarpeted floors and few other soft furnishings. This can look very smart but there isn’t much to absorb noise so sound bounces around off the hard surfaces. Perhaps some carpets, cushions and fabric wall hangings would help? You can also suspend things from the ceiling that will help baffle noise.

Good stuff Coles, that is what I would have suggested too.
You can also separately try putting a heavy blanket over the window ope at night and see what effect that has, then a thicker curtain, preferably touching the ground, might be helpful
I would imagine it’s the air vent
Although if it’s an old house this must be a recently installed vent no?
Does the room have wooden floors or carpets?

Good points.
In general if people are have problems with noise and they have double/triple glazing, the probelm is not the windows, unless of course the windows have poor seals.

Secondary glazing systems will perform better in installations where sound insulation is not limited by poor sealing or by flanking sound paths such as through doors or acoustically weak parts of window bays.

Air gaps are very important as noise propagates through them in a similar way water would. A small gap can contribute a large % of the noise in the house.

Common air gaps include:
Wall–floor gaps
Gaps around doors
Poor window seals
Unsealed pipe runs
Unsealed cable runs
Porous blockwork

Eliminate these sources (except blockwork) first before tackling anything else.

If noise is still a problem, its possible that noise could be transmitted through the floor ceiling (as is the case where i live) or the walls … 099123.pdf

General principal of noise reduction is to put the noise reducer as close to the noise source as possible.
In your case a high fence or planted barrier close to the road will probably be your best bet.

That and the air vents.

I have double-glazed windows and a train track in front of the house (in a country with lots of fast trains).
When I bought the place, I asked an architect about putting in triple-glazing and he said it would be a waste of money, as any opening at all in the house would leave the noise in anyhow, even if its at the other side of the house.
I like fresh air, I don’t want to live in a hermetically sealed house.
I learned to love the sound of trains. I imagine its harder with cars though, more random noise…
Thick wool curtains might help.

+1. I have a well sealed house. But the vent on the sitting room wall might as well be a loudspeaker. Noises from any direction around the house radiate from the vent, as if they were coming from that side. Fortunately, most of my sounds are cows mooing, the sea crashing on sand, and the wind in the trees, none of which I would want to shut out.