How do I improve the noise insulation of my house/dwelling?

This is one of the most commonly asked questions of noise consultants.
Firstly you should consider whether better insulation is really
essential. The method of noise insulation will depend on the exact
situation, so the advice of a competent person should be sought at an
early stage. Sound insulation is most often asked for in order to keep
out unwanted noise, but is occasionally requested for the purpose of
minimizing disturbance to others. The following ideas may serve as
guidelines.

When the noise is from an external source such as a main road it may
be possible, if planning authorities permit, to screen with a noise
barrier. These can be effective providing that the direct line of sight
between traffic and house is concealed by the barrier.

The weak point for sound transmission to and from a building is most
often via the windows. Double glazing will usually afford noticeably
better protection than single glazing, but in areas of high external
noise it might be preferable to have double windows with a large air
gap and acoustic absorbent material in the reveals. A drawback of
improving external insulation is that, for some people, the resultant
lower background level can itself be disturbing; it can also make noise
transmission through party walls more apparent. The fitting of new
windows may reduce the level of air ventilation, and it will be vital
to compensate for this, if necessary with a noise attenuating system.

You may also need to consider noise penetration through the roof,
floors, ceilings and walls.

Noise through party walls can be reduced by the addition of a false
wall. This is constructed from a layer of sound insulating material,
commonly plasterboard, separated from the party wall by a large void
containing acoustic quilting. The false wall must not be connected to
the party wall because that would allow sound transmission paths. The
quality of construction is an important consideration if optimal levels
of attenuation are desired. It is advisable to contact an independent
noise consultant before allowing any building works to commence.