Reducing Noise Through Windows

General Principles

The main factors in window noise reduction in order of importance are:

1. Glass Thickness

Thicker glass will give a better result. (Laminated glass is slightly better than solid glass of similar thickness as the laminated layer provides additional ‘Damping’)

2. Air Gap,

A secondary window system with a 100mm air gap will perform much better acoustically than a Insulated Glass Unit (IGU).

Thermally however the performance will be lower.

Having the glass thickness of the two panes vary by more than 50% improves the accoustic performance.

3. Sealing

Effective compression sealing around opening sashes, and sealing around the frame will prevent noise ‘getting around’ the window.

Noise Levels

Noise is measured in Decibels (dB).

The scale  is logarithmic, which means that each 10dB increase means the sound is twice as loud.

External Noise Levels

Conversation 65dB

Aircraft    65dB

Traffic    70 – 80dB

Construction  75dB (measured at your property boundary)

Recomended Internal Noise levels

Bedroom    30 – 35dB

Living Room    35 – 40dB

Noise Insulation Performance

Sometimes you will see performance quoted as a Sound Transmission Class (STC) others use Weighted Sound Reduction (Rw) values. Both units are essentially the same  and are equivalent to decibels,

Installing windows rated 30 Rw, or STC 30, will reduce an external 75dB noise  by 30dB, to an internal noise level of 45dB.

Approximate performance of various glazing  systems are:

TYPE THICKNESS mm STC / Rw dB
Single – Clear glass 3 30
Single – Clear glass 6 32
Single – Clear glass 10 36
Single – Laminate 6.4 33
Single – Laminate 7.5 34
Single – Laminate 10.3 37
Double – IGU 6  – 8mm air gap  –  4 34
Double – Secondary 6  – 100mm air gap –  4 46

You will need to talk to your proposed window suppliers to establish the exact performance and costs.

NEIGHBOURS

Would you worry if you saw this guy (from Jim’s Jihad?) mowing the lawn next door?

Unlikely. . .  but it does illustrate the fact that neighbours can have a big effect on your enjoyment, or otherwise, of your house.

In fact 20% of us have fallen out with a neighbour in the last 5 years, and only 1% said all their neighbours were great.

Top Five Reasons for Neighbour Problems

Domain recently carried out a survey, and here are the top 5 reasons why people had problems with their neighbours:

  • Loud music (30%)
  • Late night parties (28%)
  • Barking dogs (26%)
  • Overhearing Shouting and arguing (16%)
  • Untidy property (15%)

Its often said “Tall fences make good neighbours’. . . .  but with the top four problems being noise related perhaps it should be “Tall fences and Good Sound Proofing make good neighbours!”

Before Buying a Block

If you are buying on a new subdivision who your neighbour will be is always a lottery . . . . so corner block have always been attractive to me as  it means one less neighbour.

If I was looking at a vacant block (or Knock down rebuild) in an established suburb I would aim to make visits:

  • During the middle of a working day to check for barking dogs.
  • Mid to late evening to check for loud music.

At Selection/PreStart

If you want better sound proofing two things you should consider are:

Smaller Windows – As solid walls have better sound reduction than Glass

Double Glazing – Much better noise insulation than single panes

See Noise for more posts

 

Photo courtesy of  neighborshame.com where you  will find more bad neighbour photos.

 

Noise Insulation – Plasterboard Options

There are a few plasterboard options when looking to improve the noise insulation.

These options in increasing order of cost are:

Differing Thickness On Each Face

By using different and thicker plasterboards on each wall face, say 13mm and 16mm, it will change the resonant frequency to disrupt sound transmission

Acoustic Plasterboard

It is possible to order a special accoustic plasterboard which has a denser core than the standard board.

Double Layers of Plasterboard

The most effective, but most expensive, option is to use a double layer of plasterboard on each face of the walls and the ceiling. Again using different thickness will help.

Make sure the sheets overlap and use an acoustic glue between the boards.

One advantage of the double sheet is that it will also improve the fire resistance of the walls and ceiling.

Also

Use an Acoustic Caulk at wall to floor, wall to ceiling, and even at wall sheet joints.

Use solid doors with rubber seals.

For similar posts see: Noise

 

Sound Insulation Batts

Imagine the standard internal stud wall in your new house.

  • A sheet of fairly thin material (plasterboard).
  • An air space retained by timber walls.
  • Another thin sheet of material.

Sounds a bit like a Drum doesn’t it?……………It’s no wonder sound transmits easily from room to room.

If you are having a 2 storey house that drum effect will be the same between the floors with the added problem of someone walking on the top of the “drum”.

To make things quieter one solution is to fill the air space with something that can absorb the noise.

You can use standard wall  insulation batts, but for the best performance it is better to go for an Accoustic Batt.

The Accoustic Batts are  more expensive (typically 60-70% more) but being much denser absorb a lot more sound.

If you decide to go for sound insulation batts a key issue in the effectiveness will be the quality of the installation. Every gap must be fully filled with insulation, any missing areas and noise will get through.

An added advantage of putting sound insulation in internal walls  is that it increases the effect of Buffer Zones in keeping heating and cooling costs down.

A disadvantage is that if you were used to shouting to get the attention of someone in another room that won’t work with good sound insulation.

In high end houses it’s not unusual to wrap the toilet waste pipes in accoustic insulation so people downstairs can’t hear an upstairs toilet flush!
 

Also see Reducing External Noise

 

Reducing External Noise

 

It’s not always possible to build in a quiet area so there are a number of techniques for reducing noise that you can use in your new home.

Here is a quick review of the options:

  • Minimising  windows facing the noise. OK  as long as the noise source isn’t on the North side otherwise you loose the effect of sunlight in the house.
  • Screen walls. These reflect sound. If you are going for this approach at the front of the house put some thought into the design of the wall. A plain wall just looks ugly.
  • Buffer zones. I’ve previously talked about Buffer Zones in relation to heating and cooling but they can work well in keeping some rooms quieter.
  • Soft landscaping. Absorbs sound, rather than paving which reflects sound. If possible a landscaped bund (low embankment) can be effective.
  • Roofing material.  Tiles will absorb more noise than a colorbond roof.
  • Acoustic Plasterboard. It’s possible, on special order, to get a range of Plaster boards including ones with a denser core that help to reduce sound transmission. A second layer of plasterboard at a different thickness to the original can help.
  • Ceiling  and wall insulation. Ordinary heat insulation batts will absorb noise but for the best performance it is better to use ƒspecialist acoustic insulation.
  • Glazing. Thicker glass will help but double glazing with a larger air will give better performance. The use of  laminated glass can also improve performance.
  • Curtains Heavy curtains can be effective, when they are closed.
  • Solid Doors. Better performance than the standard lightweight doors.
  • Windows and door seals. Need to be  properly fitted, and maintained.
  • ƒRefrigerated Air Conditioning.  Unlike evaporative cooling this doesn’t rely on open windows.
  • Sound absorbing materials Although acoustic tiles, carpets, underlays don’t stop noise getting in they will absorb it better than hard surfaces like tiles or wood floors.

To get effective performance  will require a range of the above options rather than a single ‘Magic Bullet’.

When you are considering these options its also worth bearing in mind that most of these improvements will also improve the thermal performance of your new house.

 

For more posts about plans see the Design Category.

To save money on Heating and Cooling see Insulation